diff --git a/.github/workflows/semantic-pull-request.yml b/.github/workflows/semantic-pull-request.yml
index 4e5c9e59de96..28975eae73bf 100644
--- a/.github/workflows/semantic-pull-request.yml
+++ b/.github/workflows/semantic-pull-request.yml
@@ -30,6 +30,7 @@ jobs:
             build
             guix
             ci
+            lint
             chore
             revert
             trivial
diff --git a/src/.clang-tidy b/src/.clang-tidy
index 76978140ecd7..ad82694d875d 100644
--- a/src/.clang-tidy
+++ b/src/.clang-tidy
@@ -26,3 +26,4 @@ readability-redundant-string-init,
 CheckOptions:
  - key: performance-move-const-arg.CheckTriviallyCopyableMove
    value: false
+HeaderFilterRegex: '.'
diff --git a/src/active/dkgsessionhandler.cpp b/src/active/dkgsessionhandler.cpp
index c0ed65b75402..1c74095ad7d2 100644
--- a/src/active/dkgsessionhandler.cpp
+++ b/src/active/dkgsessionhandler.cpp
@@ -343,7 +343,7 @@ static void RelayInvToParticipants(const CDKGSession& session, const CConnman& c
                  "HasMasternodeQuorumNodes[%d] for quorumHash[%s] forMember[%s] relayMembers[%s]",
                  inv.ToString(), relayMembers.size(), connman.GetNodeCount(ConnectionDirection::Both),
                  connman.GetNetworkActive(),
-                 connman.HasMasternodeQuorumNodes(session.GetParams().type, session.BlockIndex()->GetBlockHash()),
+                 connman.HasMasternodeQuorumNodes(session.GetType(), session.BlockIndex()->GetBlockHash()),
                  session.BlockIndex()->GetBlockHash().ToString(), session.ProTx().ToString().substr(0, 4), ss.str());
 
     std::stringstream ss2;
diff --git a/src/bls/bls.h b/src/bls/bls.h
index a99cec3114cf..6c3a7f2010e9 100644
--- a/src/bls/bls.h
+++ b/src/bls/bls.h
@@ -390,7 +390,7 @@ class CBLSLazyWrapper
 private:
     mutable std::mutex mutex;
 
-    mutable std::array<uint8_t, BLSObject::SerSize> vecBytes;
+    mutable std::array<uint8_t, BLSObject::SerSize> vecBytes{};
 
     mutable BLSObject obj;
     mutable bool objInitialized{false};
@@ -403,7 +403,6 @@ class CBLSLazyWrapper
 
 public:
     CBLSLazyWrapper() :
-        vecBytes{},
         bufLegacyScheme(bls::bls_legacy_scheme.load())
     {}
 
diff --git a/src/chain.h b/src/chain.h
index 47d1e3096774..4236e5a7adff 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -35,7 +35,7 @@ static constexpr int64_t TIMESTAMP_WINDOW = MAX_FUTURE_BLOCK_TIME;
  */
 static constexpr int64_t MAX_BLOCK_TIME_GAP = 25 * 60;
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class CBlockFileInfo
 {
diff --git a/src/coinjoin/coinjoin.h b/src/coinjoin/coinjoin.h
index 9a15be8b6c03..461aa16ec991 100644
--- a/src/coinjoin/coinjoin.h
+++ b/src/coinjoin/coinjoin.h
@@ -34,7 +34,7 @@ class CChainLocksHandler;
 class CInstantSendManager;
 } // namespace llmq
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 // timeouts
 static constexpr int COINJOIN_AUTO_TIMEOUT_MIN = 5;
diff --git a/src/crypto/ripemd160.cpp b/src/crypto/ripemd160.cpp
index 29a4ad906fc7..a2f7c6e1563b 100644
--- a/src/crypto/ripemd160.cpp
+++ b/src/crypto/ripemd160.cpp
@@ -239,7 +239,7 @@ void Transform(uint32_t* s, const unsigned char* chunk)
 
 ////// RIPEMD160
 
-CRIPEMD160::CRIPEMD160() : bytes(0)
+CRIPEMD160::CRIPEMD160()
 {
     ripemd160::Initialize(s);
 }
diff --git a/src/crypto/ripemd160.h b/src/crypto/ripemd160.h
index 025121f24ad1..d4a526e5587f 100644
--- a/src/crypto/ripemd160.h
+++ b/src/crypto/ripemd160.h
@@ -14,7 +14,7 @@ class CRIPEMD160
 private:
     uint32_t s[5];
     unsigned char buf[64];
-    uint64_t bytes;
+    uint64_t bytes{0};
 
 public:
     static const size_t OUTPUT_SIZE = 20;
diff --git a/src/crypto/sha1.cpp b/src/crypto/sha1.cpp
index 1fb9bb2b72f2..2610108f6075 100644
--- a/src/crypto/sha1.cpp
+++ b/src/crypto/sha1.cpp
@@ -146,7 +146,7 @@ void Transform(uint32_t* s, const unsigned char* chunk)
 
 ////// SHA1
 
-CSHA1::CSHA1() : bytes(0)
+CSHA1::CSHA1()
 {
     sha1::Initialize(s);
 }
diff --git a/src/crypto/sha1.h b/src/crypto/sha1.h
index f1b7dffab43d..e991362393cf 100644
--- a/src/crypto/sha1.h
+++ b/src/crypto/sha1.h
@@ -14,7 +14,7 @@ class CSHA1
 private:
     uint32_t s[5];
     unsigned char buf[64];
-    uint64_t bytes;
+    uint64_t bytes{0};
 
 public:
     static const size_t OUTPUT_SIZE = 20;
diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
index 884719a1b097..c99b5697366d 100644
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -690,7 +690,7 @@ std::string SHA256AutoDetect(sha256_implementation::UseImplementation use_implem
 
 ////// SHA-256
 
-CSHA256::CSHA256() : bytes(0)
+CSHA256::CSHA256()
 {
     sha256::Initialize(s);
 }
diff --git a/src/crypto/sha256.h b/src/crypto/sha256.h
index 60b2237a7430..456c65746c32 100644
--- a/src/crypto/sha256.h
+++ b/src/crypto/sha256.h
@@ -15,7 +15,7 @@ class CSHA256
 private:
     uint32_t s[8];
     unsigned char buf[64];
-    uint64_t bytes;
+    uint64_t bytes{0};
 
 public:
     static const size_t OUTPUT_SIZE = 32;
diff --git a/src/crypto/sha512.cpp b/src/crypto/sha512.cpp
index 59b79609dd8c..5e4a1c3cc329 100644
--- a/src/crypto/sha512.cpp
+++ b/src/crypto/sha512.cpp
@@ -151,7 +151,7 @@ void Transform(uint64_t* s, const unsigned char* chunk)
 
 ////// SHA-512
 
-CSHA512::CSHA512() : bytes(0)
+CSHA512::CSHA512()
 {
     sha512::Initialize(s);
 }
diff --git a/src/crypto/sha512.h b/src/crypto/sha512.h
index 7356dff6d9b3..4d5815afa7c4 100644
--- a/src/crypto/sha512.h
+++ b/src/crypto/sha512.h
@@ -14,7 +14,7 @@ class CSHA512
 private:
     uint64_t s[8];
     unsigned char buf[128];
-    uint64_t bytes;
+    uint64_t bytes{0};
 
 public:
     static constexpr size_t OUTPUT_SIZE = 64;
diff --git a/src/cuckoocache.h b/src/cuckoocache.h
index 22c06d89735a..833254b40b36 100644
--- a/src/cuckoocache.h
+++ b/src/cuckoocache.h
@@ -164,7 +164,7 @@ class cache
     std::vector<Element> table;
 
     /** size stores the total available slots in the hash table */
-    uint32_t size;
+    uint32_t size{0};
 
     /** The bit_packed_atomic_flags array is marked mutable because we want
      * garbage collection to be allowed to occur from const methods */
@@ -181,7 +181,7 @@ class cache
      * decremented on insert and reset to the new number of inserts which would
      * cause the epoch to reach epoch_size when it reaches zero.
      */
-    uint32_t epoch_heuristic_counter;
+    uint32_t epoch_heuristic_counter{0};
 
     /** epoch_size is set to be the number of elements supposed to be in a
      * epoch. When the number of non-erased elements in an epoch
@@ -191,12 +191,12 @@ class cache
      * one "dead" which has been erased, one "dying" which has been marked to be
      * erased next, and one "living" which new inserts add to.
      */
-    uint32_t epoch_size;
+    uint32_t epoch_size{0};
 
     /** depth_limit determines how many elements insert should try to replace.
      * Should be set to log2(n).
      */
-    uint8_t depth_limit;
+    uint8_t depth_limit{0};
 
     /** hash_function is a const instance of the hash function. It cannot be
      * static or initialized at call time as it may have internal state (such as
@@ -320,8 +320,7 @@ class cache
     /** You must always construct a cache with some elements via a subsequent
      * call to setup or setup_bytes, otherwise operations may segfault.
      */
-    cache() : table(), size(), collection_flags(0), epoch_flags(),
-    epoch_heuristic_counter(), epoch_size(), depth_limit(0), hash_function()
+    cache() : table(), collection_flags(0), epoch_flags(), hash_function()
     {
     }
 
diff --git a/src/cxxtimer.hpp b/src/cxxtimer.hpp
index 0b58b5d97134..509d6c5f82d4 100644
--- a/src/cxxtimer.hpp
+++ b/src/cxxtimer.hpp
@@ -118,20 +118,17 @@ class Timer {
     typename duration_t::rep count() const;
 
 private:
-
-    bool started_;
-    bool paused_;
-    std::chrono::steady_clock::time_point reference_;
-    std::chrono::duration<long double> accumulated_;
+    bool started_{false};
+    bool paused_{false};
+    std::chrono::steady_clock::time_point reference_{std::chrono::steady_clock::now()};
+    std::chrono::duration<long double> accumulated_{std::chrono::duration<long double>(0)};
 };
 
 }
 
 
-inline cxxtimer::Timer::Timer(bool start) :
-        started_(false), paused_(false),
-        reference_(std::chrono::steady_clock::now()),
-        accumulated_(std::chrono::duration<long double>(0)) {
+inline cxxtimer::Timer::Timer(bool start)
+{
     if (start) {
         this->start();
     }
diff --git a/src/dbwrapper.h b/src/dbwrapper.h
index bd6e847180a6..9f04c8523266 100644
--- a/src/dbwrapper.h
+++ b/src/dbwrapper.h
@@ -79,13 +79,13 @@ class CDBBatch
     CDataStream ssKey;
     CDataStream ssValue;
 
-    size_t size_estimate;
+    size_t size_estimate{0};
 
 public:
     /**
      * @param[in] _parent    CDBWrapper that this batch is to be submitted to
      */
-    explicit CDBBatch(const CDBWrapper &_parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION), size_estimate(0) { };
+    explicit CDBBatch(const CDBWrapper& _parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION) {};
 
     void Clear()
     {
diff --git a/src/evo/deterministicmns.h b/src/evo/deterministicmns.h
index 1bdcf7343e96..4a0661633ad7 100644
--- a/src/evo/deterministicmns.h
+++ b/src/evo/deterministicmns.h
@@ -40,7 +40,7 @@ class CSpecialTxProcessor;
 class TxValidationState;
 struct RPCResult;
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class CDeterministicMN
 {
diff --git a/src/evo/dmn_types.h b/src/evo/dmn_types.h
index d532c6b3a667..bdf79e84c4f1 100644
--- a/src/evo/dmn_types.h
+++ b/src/evo/dmn_types.h
@@ -53,7 +53,7 @@ constexpr auto Invalid = mntype_struct{
 
 } // namespace dmn_types
 
-[[nodiscard]] constexpr const dmn_types::mntype_struct GetMnType(MnType type)
+[[nodiscard]] constexpr dmn_types::mntype_struct GetMnType(MnType type)
 {
     switch (type) {
         case MnType::Regular: return dmn_types::Regular;
diff --git a/src/evo/mnhftx.h b/src/evo/mnhftx.h
index 2f399412c24c..f1606d226b44 100644
--- a/src/evo/mnhftx.h
+++ b/src/evo/mnhftx.h
@@ -46,7 +46,7 @@ class MNHFTx
     SERIALIZE_METHODS(MNHFTx, obj)
     {
         READWRITE(obj.versionBit, obj.quorumHash);
-        READWRITE(CBLSSignatureVersionWrapper(const_cast<CBLSSignature&>(obj.sig), /* fLegacy= */ false));
+        READWRITE(CBLSSignatureVersionWrapper(const_cast<CBLSSignature&>(obj.sig), /*legacy=*/false));
     }
 
     std::string ToString() const;
diff --git a/src/evo/smldiff.h b/src/evo/smldiff.h
index 0154403d840b..36eb066f73a7 100644
--- a/src/evo/smldiff.h
+++ b/src/evo/smldiff.h
@@ -29,7 +29,7 @@ class CQuorumBlockProcessor;
 class CQuorumManager;
 } // namespace llmq
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 /// P2P messages
 
diff --git a/src/evo/specialtxman.h b/src/evo/specialtxman.h
index de293d0dfaba..4980c11324aa 100644
--- a/src/evo/specialtxman.h
+++ b/src/evo/specialtxman.h
@@ -33,7 +33,7 @@ class CQuorumManager;
 class CQuorumSnapshotManager;
 } // namespace llmq
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class CSpecialTxProcessor
 {
diff --git a/src/governance/classes.h b/src/governance/classes.h
index 50c7f1e2ef9c..f68691bb03ce 100644
--- a/src/governance/classes.h
+++ b/src/governance/classes.h
@@ -102,7 +102,7 @@ class CSuperblock : public CGovernanceObject
         return nBlockHeight;
     }
 
-    const uint256 GetGovernanceObjHash() const { return nGovObjHash; }
+    uint256 GetGovernanceObjHash() const { return nGovObjHash; }
 
     int CountPayments() const { return (int)vecPayments.size(); }
     bool GetPayment(int nPaymentIndex, CGovernancePayment& paymentRet);
diff --git a/src/governance/governance.h b/src/governance/governance.h
index a8d5f324acbc..a90dc0e250ca 100644
--- a/src/governance/governance.h
+++ b/src/governance/governance.h
@@ -52,25 +52,20 @@ using vote_time_pair_t = std::pair<CGovernanceVote, int64_t>;
 static constexpr int RATE_BUFFER_SIZE = 5;
 static constexpr bool DEFAULT_GOVERNANCE_ENABLE{true};
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class CRateCheckBuffer
 {
 private:
     std::vector<int64_t> vecTimestamps;
 
-    int nDataStart;
-
-    int nDataEnd;
-
-    bool fBufferEmpty;
+    int nDataStart{0};
+    int nDataEnd{0};
+    bool fBufferEmpty{true};
 
 public:
     CRateCheckBuffer() :
-        vecTimestamps(RATE_BUFFER_SIZE),
-        nDataStart(0),
-        nDataEnd(0),
-        fBufferEmpty(true)
+        vecTimestamps(RATE_BUFFER_SIZE)
     {
     }
 
diff --git a/src/governance/object.h b/src/governance/object.h
index 9e149e4ac9af..f1df2ecd069a 100644
--- a/src/governance/object.h
+++ b/src/governance/object.h
@@ -24,7 +24,7 @@ class ChainstateManager;
 class CMasternodeMetaMan;
 struct RPCResult;
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 static constexpr double GOVERNANCE_FILTER_FP_RATE = 0.001;
 static constexpr CAmount GOVERNANCE_PROPOSAL_FEE_TX = (1 * COIN);
diff --git a/src/governance/validators.cpp b/src/governance/validators.cpp
index bbe10d90439d..498796da955d 100644
--- a/src/governance/validators.cpp
+++ b/src/governance/validators.cpp
@@ -18,7 +18,6 @@ const size_t MAX_NAME_SIZE = 40;
 
 CProposalValidator::CProposalValidator(const std::string& strHexData, bool fAllowScript) :
     objJSON(UniValue::VOBJ),
-    fJSONValid(false),
     fAllowScript(fAllowScript),
     strErrorMessages()
 {
diff --git a/src/governance/validators.h b/src/governance/validators.h
index b7daafe52c9f..39685e223d80 100644
--- a/src/governance/validators.h
+++ b/src/governance/validators.h
@@ -13,7 +13,7 @@ class CProposalValidator
 {
 private:
     UniValue objJSON;
-    bool fJSONValid;
+    bool fJSONValid{false};
     bool fAllowScript;
     std::string strErrorMessages;
 
diff --git a/src/governance/votedb.cpp b/src/governance/votedb.cpp
index 6ffc8eeffffd..b1768f8b0346 100644
--- a/src/governance/votedb.cpp
+++ b/src/governance/votedb.cpp
@@ -5,7 +5,6 @@
 #include <governance/votedb.h>
 
 CGovernanceObjectVoteFile::CGovernanceObjectVoteFile() :
-    nMemoryVotes(0),
     listVotes(),
     mapVoteIndex()
 {
diff --git a/src/governance/votedb.h b/src/governance/votedb.h
index 646544c3de77..169196cb9ff8 100644
--- a/src/governance/votedb.h
+++ b/src/governance/votedb.h
@@ -32,7 +32,7 @@ class CGovernanceObjectVoteFile
     using vote_m_t = std::map<uint256, vote_l_t::iterator>;
 
 private:
-    int nMemoryVotes;
+    int nMemoryVotes{0};
 
     vote_l_t listVotes;
 
diff --git a/src/key.h b/src/key.h
index babffd406b0a..c1688815a517 100644
--- a/src/key.h
+++ b/src/key.h
@@ -48,10 +48,10 @@ class CKey
 private:
     //! Whether this private key is valid. We check for correctness when modifying the key
     //! data, so fValid should always correspond to the actual state.
-    bool fValid;
+    bool fValid{false};
 
     //! Whether the public key corresponding to this private key is (to be) compressed.
-    bool fCompressed;
+    bool fCompressed{false};
 
     //! The actual byte data
     std::vector<unsigned char, secure_allocator<unsigned char> > keydata;
@@ -61,7 +61,7 @@ class CKey
 
 public:
     //! Construct an invalid private key.
-    CKey() : fValid(false), fCompressed(false)
+    CKey()
     {
         // Important: vch must be 32 bytes in length to not break serialization
         keydata.resize(32);
diff --git a/src/llmq/blockprocessor.h b/src/llmq/blockprocessor.h
index e44506131036..15ca83307117 100644
--- a/src/llmq/blockprocessor.h
+++ b/src/llmq/blockprocessor.h
@@ -31,7 +31,7 @@ class CDeterministicMNManager;
 class CEvoDB;
 class CNode;
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 namespace llmq
 {
diff --git a/src/llmq/dkgsession.h b/src/llmq/dkgsession.h
index 16b2e1416653..f9a4ce756e92 100644
--- a/src/llmq/dkgsession.h
+++ b/src/llmq/dkgsession.h
@@ -389,7 +389,7 @@ class CDKGSession
     [[nodiscard]] const Uint256HashSet& RelayMembers() const { return relayMembers; }
     [[nodiscard]] const CBlockIndex* BlockIndex() const { return m_quorum_base_block_index; }
     [[nodiscard]] const uint256& ProTx() const { return myProTxHash; }
-    [[nodiscard]] const Consensus::LLMQParams GetParams() const { return params; }
+    [[nodiscard]] Consensus::LLMQType GetType() const { return params.type; }
 
 protected:
     virtual bool MaybeDecrypt(const CBLSIESMultiRecipientObjects<CBLSSecretKey>& obj, size_t idx,
diff --git a/src/masternode/meta.h b/src/masternode/meta.h
index 5e7729a9390f..4342e65607c1 100644
--- a/src/masternode/meta.h
+++ b/src/masternode/meta.h
@@ -127,7 +127,7 @@ class MasternodeMetaStore
         std::vector<uint256> tmpUsedMasternodes;
         s >> tmpMetaInfo >> nDsqCount >> tmpUsedMasternodes;
         for (auto& mm : tmpMetaInfo) {
-            metaInfos.emplace(mm.m_protx_hash, CMasternodeMetaInfo{std::move(mm)});
+            metaInfos.emplace(mm.m_protx_hash, CMasternodeMetaInfo{mm});
         }
 
         // Convert vector to deque and build unordered_set for O(1) lookups
diff --git a/src/node/blockstorage.h b/src/node/blockstorage.h
index b627c26162fd..2cfae856c2cc 100644
--- a/src/node/blockstorage.h
+++ b/src/node/blockstorage.h
@@ -16,7 +16,7 @@
 #include <unordered_map>
 #include <vector>
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class ArgsManager;
 class BlockValidationState;
diff --git a/src/policy/fees.cpp b/src/policy/fees.cpp
index e0586637450a..03b629e7b9e6 100644
--- a/src/policy/fees.cpp
+++ b/src/policy/fees.cpp
@@ -543,7 +543,6 @@ bool CBlockPolicyEstimator::_removeTx(const uint256& hash, bool inBlock)
 }
 
 CBlockPolicyEstimator::CBlockPolicyEstimator()
-    : nBestSeenHeight(0), firstRecordedHeight(0), historicalFirst(0), historicalBest(0), trackedTxs(0), untrackedTxs(0)
 {
     static_assert(MIN_BUCKET_FEERATE > 0, "Min feerate must be nonzero");
     size_t bucketIndex = 0;
diff --git a/src/policy/fees.h b/src/policy/fees.h
index 3a0ed2dc1b11..45bc40ab75c0 100644
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -240,16 +240,16 @@ class CBlockPolicyEstimator
 private:
     mutable Mutex m_cs_fee_estimator;
 
-    unsigned int nBestSeenHeight GUARDED_BY(m_cs_fee_estimator);
-    unsigned int firstRecordedHeight GUARDED_BY(m_cs_fee_estimator);
-    unsigned int historicalFirst GUARDED_BY(m_cs_fee_estimator);
-    unsigned int historicalBest GUARDED_BY(m_cs_fee_estimator);
+    unsigned int nBestSeenHeight GUARDED_BY(m_cs_fee_estimator){0};
+    unsigned int firstRecordedHeight GUARDED_BY(m_cs_fee_estimator){0};
+    unsigned int historicalFirst GUARDED_BY(m_cs_fee_estimator){0};
+    unsigned int historicalBest GUARDED_BY(m_cs_fee_estimator){0};
 
     struct TxStatsInfo
     {
-        unsigned int blockHeight;
-        unsigned int bucketIndex;
-        TxStatsInfo() : blockHeight(0), bucketIndex(0) {}
+        unsigned int blockHeight{0};
+        unsigned int bucketIndex{0};
+        TxStatsInfo() {}
     };
 
     // map of txids to information about that transaction
@@ -260,8 +260,8 @@ class CBlockPolicyEstimator
     std::unique_ptr<TxConfirmStats> shortStats PT_GUARDED_BY(m_cs_fee_estimator);
     std::unique_ptr<TxConfirmStats> longStats PT_GUARDED_BY(m_cs_fee_estimator);
 
-    unsigned int trackedTxs GUARDED_BY(m_cs_fee_estimator);
-    unsigned int untrackedTxs GUARDED_BY(m_cs_fee_estimator);
+    unsigned int trackedTxs GUARDED_BY(m_cs_fee_estimator){0};
+    unsigned int untrackedTxs GUARDED_BY(m_cs_fee_estimator){0};
 
     std::vector<double> buckets GUARDED_BY(m_cs_fee_estimator); // The upper-bound of the range for the bucket (inclusive)
     std::map<double, unsigned int> bucketMap GUARDED_BY(m_cs_fee_estimator); // Map of bucket upper-bound to index into all vectors by bucket
diff --git a/src/qt/addressbookpage.cpp b/src/qt/addressbookpage.cpp
index 9f2b162eb948..7a96643225df 100644
--- a/src/qt/addressbookpage.cpp
+++ b/src/qt/addressbookpage.cpp
@@ -67,7 +67,6 @@ class AddressBookSortFilterProxyModel final : public QSortFilterProxyModel
 AddressBookPage::AddressBookPage(Mode _mode, Tabs _tab, QWidget* parent) :
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::AddressBookPage),
-    model(nullptr),
     mode(_mode),
     tab(_tab)
 {
diff --git a/src/qt/addressbookpage.h b/src/qt/addressbookpage.h
index 2446443e5d3f..a21c6830f06f 100644
--- a/src/qt/addressbookpage.h
+++ b/src/qt/addressbookpage.h
@@ -48,7 +48,7 @@ public Q_SLOTS:
 
 private:
     Ui::AddressBookPage *ui;
-    AddressTableModel *model;
+    AddressTableModel* model{nullptr};
     Mode mode;
     Tabs tab;
     QString returnValue;
diff --git a/src/qt/appearancewidget.h b/src/qt/appearancewidget.h
index 1929d0b6b33a..24b2689c9a66 100644
--- a/src/qt/appearancewidget.h
+++ b/src/qt/appearancewidget.h
@@ -24,7 +24,7 @@ class AppearanceWidget : public QWidget
     Q_OBJECT
 
 public:
-    explicit AppearanceWidget(QWidget* parent = 0);
+    explicit AppearanceWidget(QWidget* parent = nullptr);
     ~AppearanceWidget();
 
     void setModel(OptionsModel* model);
diff --git a/src/qt/askpassphrasedialog.cpp b/src/qt/askpassphrasedialog.cpp
index 9f2e6b41533b..ad4f0f8f84ff 100644
--- a/src/qt/askpassphrasedialog.cpp
+++ b/src/qt/askpassphrasedialog.cpp
@@ -25,8 +25,6 @@ AskPassphraseDialog::AskPassphraseDialog(Mode _mode, QWidget *parent, SecureStri
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::AskPassphraseDialog),
     mode(_mode),
-    model(nullptr),
-    fCapsLock(false),
     m_passphrase_out(passphrase_out)
 {
     ui->setupUi(this);
diff --git a/src/qt/askpassphrasedialog.h b/src/qt/askpassphrasedialog.h
index 3157e24ef050..88d49f5e7fdb 100644
--- a/src/qt/askpassphrasedialog.h
+++ b/src/qt/askpassphrasedialog.h
@@ -39,8 +39,8 @@ class AskPassphraseDialog : public QDialog
 private:
     Ui::AskPassphraseDialog *ui;
     Mode mode;
-    WalletModel *model;
-    bool fCapsLock;
+    WalletModel* model{nullptr};
+    bool fCapsLock{false};
     SecureString* m_passphrase_out;
 
 private Q_SLOTS:
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index aa895e627754..49be7fe28714 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -231,13 +231,8 @@ void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, cons
 static int qt_argc = 1;
 static const char* qt_argv = "dash-qt";
 
-BitcoinApplication::BitcoinApplication():
-    QApplication(qt_argc, const_cast<char **>(&qt_argv)),
-    optionsModel(nullptr),
-    clientModel(nullptr),
-    window(nullptr),
-    pollShutdownTimer(nullptr),
-    returnValue(0)
+BitcoinApplication::BitcoinApplication()
+    : QApplication(qt_argc, const_cast<char**>(&qt_argv))
 {
     RegisterMetaTypes();
     // Qt runs setlocale(LC_ALL, "") on initialization.
diff --git a/src/qt/bitcoin.h b/src/qt/bitcoin.h
index 0cf8ee03bcfc..077253c3bd91 100644
--- a/src/qt/bitcoin.h
+++ b/src/qt/bitcoin.h
@@ -93,15 +93,15 @@ public Q_SLOTS:
 
 private:
     std::optional<InitExecutor> m_executor;
-    OptionsModel *optionsModel;
-    ClientModel *clientModel;
-    BitcoinGUI *window;
-    QTimer *pollShutdownTimer;
+    OptionsModel* optionsModel{nullptr};
+    ClientModel* clientModel{nullptr};
+    BitcoinGUI* window{nullptr};
+    QTimer* pollShutdownTimer{nullptr};
 #ifdef ENABLE_WALLET
     PaymentServer* paymentServer{nullptr};
     WalletController* m_wallet_controller{nullptr};
 #endif
-    int returnValue;
+    int returnValue{0};
     std::unique_ptr<QWidget> shutdownWindow;
     SplashScreen* m_splash = nullptr;
     std::unique_ptr<interfaces::Node> m_node;
diff --git a/src/qt/bitcoinamountfield.cpp b/src/qt/bitcoinamountfield.cpp
index d71e08fd2ee8..9b6391149076 100644
--- a/src/qt/bitcoinamountfield.cpp
+++ b/src/qt/bitcoinamountfield.cpp
@@ -185,9 +185,8 @@ class AmountLineEdit: public QLineEdit
 
 #include <qt/bitcoinamountfield.moc>
 
-BitcoinAmountField::BitcoinAmountField(QWidget *parent) :
-    QWidget(parent),
-    amount(nullptr)
+BitcoinAmountField::BitcoinAmountField(QWidget* parent)
+    : QWidget(parent)
 {
     amount = new AmountLineEdit(this);
     amount->setLocale(QLocale::c());
diff --git a/src/qt/bitcoinamountfield.h b/src/qt/bitcoinamountfield.h
index 5bb84acc537c..d5ea9b9b4469 100644
--- a/src/qt/bitcoinamountfield.h
+++ b/src/qt/bitcoinamountfield.h
@@ -72,7 +72,7 @@ class BitcoinAmountField: public QWidget
     bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
-    AmountLineEdit *amount;
+    AmountLineEdit* amount{nullptr};
     BitcoinUnits *units;
 
     void unitChanged(int idx);
diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index db33a094ea82..249e4d25d751 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -2144,9 +2144,7 @@ bool BitcoinGUI::isPrivacyModeActivated() const
     return m_mask_values_action->isChecked();
 }
 
-UnitDisplayStatusBarControl::UnitDisplayStatusBarControl() :
-    optionsModel(nullptr),
-    menu(nullptr)
+UnitDisplayStatusBarControl::UnitDisplayStatusBarControl()
 {
     createContextMenu();
     setToolTip(tr("Unit to show amounts in. Click to select another unit."));
diff --git a/src/qt/bitcoingui.h b/src/qt/bitcoingui.h
index 26f73eda3e60..576605443e7c 100644
--- a/src/qt/bitcoingui.h
+++ b/src/qt/bitcoingui.h
@@ -406,8 +406,8 @@ class UnitDisplayStatusBarControl : public QLabel
     void mousePressEvent(QMouseEvent *event) override;
 
 private:
-    OptionsModel *optionsModel;
-    QMenu* menu;
+    OptionsModel* optionsModel{nullptr};
+    QMenu* menu{nullptr};
 
     /** Shows context menu with Display Unit options by the mouse coordinates */
     void onDisplayUnitsClicked(const QPoint& point);
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index 94020ba5a3a7..ce69faa428d8 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -38,8 +38,6 @@ ClientModel::ClientModel(interfaces::Node& node, OptionsModel *_optionsModel, QO
     QObject(parent),
     m_node(node),
     optionsModel(_optionsModel),
-    peerTableModel(nullptr),
-    banTableModel(nullptr),
     m_thread(new QThread(this))
 {
     cachedBestHeaderHeight = -1;
diff --git a/src/qt/clientmodel.h b/src/qt/clientmodel.h
index dcd2ba43712c..fbf325fbd8b4 100644
--- a/src/qt/clientmodel.h
+++ b/src/qt/clientmodel.h
@@ -108,9 +108,9 @@ class ClientModel : public QObject
     interfaces::Node& m_node;
     std::vector<std::unique_ptr<interfaces::Handler>> m_event_handlers;
     OptionsModel *optionsModel;
-    PeerTableModel *peerTableModel;
+    PeerTableModel* peerTableModel{nullptr};
     PeerTableSortProxy* m_peer_table_sort_proxy{nullptr};
-    BanTableModel *banTableModel;
+    BanTableModel* banTableModel{nullptr};
 
     //! A thread to interact with m_node asynchronously
     QThread* const m_thread;
diff --git a/src/qt/csvmodelwriter.cpp b/src/qt/csvmodelwriter.cpp
index 6b89497f6d4d..52cc87dc7b60 100644
--- a/src/qt/csvmodelwriter.cpp
+++ b/src/qt/csvmodelwriter.cpp
@@ -8,9 +8,9 @@
 #include <QFile>
 #include <QTextStream>
 
-CSVModelWriter::CSVModelWriter(const QString &_filename, QObject *parent) :
-    QObject(parent),
-    filename(_filename), model(nullptr)
+CSVModelWriter::CSVModelWriter(const QString& _filename, QObject* parent)
+    : QObject(parent),
+      filename(_filename)
 {
 }
 
diff --git a/src/qt/csvmodelwriter.h b/src/qt/csvmodelwriter.h
index ad247b6859b8..a1e77826a8ca 100644
--- a/src/qt/csvmodelwriter.h
+++ b/src/qt/csvmodelwriter.h
@@ -32,7 +32,7 @@ class CSVModelWriter : public QObject
 
 private:
     QString filename;
-    const QAbstractItemModel *model;
+    const QAbstractItemModel* model{nullptr};
 
     struct Column
     {
diff --git a/src/qt/editaddressdialog.cpp b/src/qt/editaddressdialog.cpp
index 179474587854..ee0711247a6a 100644
--- a/src/qt/editaddressdialog.cpp
+++ b/src/qt/editaddressdialog.cpp
@@ -12,12 +12,11 @@
 #include <QDataWidgetMapper>
 #include <QMessageBox>
 
-EditAddressDialog::EditAddressDialog(Mode _mode, QWidget *parent) :
-    QDialog(parent, GUIUtil::dialog_flags),
-    ui(new Ui::EditAddressDialog),
-    mapper(nullptr),
-    mode(_mode),
-    model(nullptr)
+
+EditAddressDialog::EditAddressDialog(Mode _mode, QWidget* parent)
+    : QDialog(parent, GUIUtil::dialog_flags),
+      ui(new Ui::EditAddressDialog),
+      mode(_mode)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/editaddressdialog.h b/src/qt/editaddressdialog.h
index f7ad80bb2df1..7bfadcfbcc80 100644
--- a/src/qt/editaddressdialog.h
+++ b/src/qt/editaddressdialog.h
@@ -49,9 +49,9 @@ public Q_SLOTS:
     QString getDuplicateAddressWarning() const;
 
     Ui::EditAddressDialog *ui;
-    QDataWidgetMapper *mapper;
+    QDataWidgetMapper* mapper{nullptr};
     Mode mode;
-    AddressTableModel *model;
+    AddressTableModel* model{nullptr};
 
     QString address;
 };
diff --git a/src/qt/intro.cpp b/src/qt/intro.cpp
index e507e922ecaf..5e0da67467f5 100644
--- a/src/qt/intro.cpp
+++ b/src/qt/intro.cpp
@@ -123,8 +123,6 @@ int GetPruneTargetGB()
 Intro::Intro(QWidget *parent, int64_t blockchain_size_gb, int64_t chain_state_size_gb) :
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::Intro),
-    thread(nullptr),
-    signalled(false),
     m_blockchain_size_gb(blockchain_size_gb),
     m_chain_state_size_gb(chain_state_size_gb),
     m_prune_target_gb{GetPruneTargetGB()}
diff --git a/src/qt/intro.h b/src/qt/intro.h
index c01d005ae243..7b34c73b025b 100644
--- a/src/qt/intro.h
+++ b/src/qt/intro.h
@@ -65,9 +65,9 @@ private Q_SLOTS:
 private:
     Ui::Intro *ui;
     bool m_prune_checkbox_is_default{true};
-    QThread *thread;
+    QThread* thread{nullptr};
     QMutex mutex;
-    bool signalled;
+    bool signalled{false};
     QString pathToCheck;
     const int64_t m_blockchain_size_gb;
     const int64_t m_chain_state_size_gb;
diff --git a/src/qt/masternodelist.h b/src/qt/masternodelist.h
index 097be4c3ac61..6d79daaa3eb8 100644
--- a/src/qt/masternodelist.h
+++ b/src/qt/masternodelist.h
@@ -40,7 +40,7 @@ class MasternodeList : public QWidget
     Q_OBJECT
 
 public:
-    explicit MasternodeList(QWidget* parent = 0);
+    explicit MasternodeList(QWidget* parent = nullptr);
     ~MasternodeList();
 
     enum {
diff --git a/src/qt/mnemonicverificationdialog.cpp b/src/qt/mnemonicverificationdialog.cpp
index 365b8e6e5dc1..8dad20998f0c 100644
--- a/src/qt/mnemonicverificationdialog.cpp
+++ b/src/qt/mnemonicverificationdialog.cpp
@@ -27,7 +27,6 @@ MnemonicVerificationDialog::MnemonicVerificationDialog(const SecureString& mnemo
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::MnemonicVerificationDialog),
     m_mnemonic(mnemonic),
-    m_mnemonic_revealed(false),
     m_view_only(viewOnly)
 {
     ui->setupUi(this);
diff --git a/src/qt/mnemonicverificationdialog.h b/src/qt/mnemonicverificationdialog.h
index 309912201c15..5d1b706d6982 100644
--- a/src/qt/mnemonicverificationdialog.h
+++ b/src/qt/mnemonicverificationdialog.h
@@ -50,7 +50,7 @@ private Q_SLOTS:
     SecureString m_mnemonic;
     std::vector<SecureString> m_words;
     QList<int> m_selected_positions;
-    bool m_mnemonic_revealed;
+    bool m_mnemonic_revealed{false};
     bool m_has_ever_revealed{false};
     bool m_view_only{false};
     class QGridLayout* m_gridLayout{nullptr};
diff --git a/src/qt/modaloverlay.cpp b/src/qt/modaloverlay.cpp
index 8467491ff2a9..ed558f836703 100644
--- a/src/qt/modaloverlay.cpp
+++ b/src/qt/modaloverlay.cpp
@@ -12,14 +12,10 @@
 #include <QEasingCurve>
 #include <QResizeEvent>
 
-ModalOverlay::ModalOverlay(bool enable_wallet, QWidget *parent) :
-QWidget(parent),
-ui(new Ui::ModalOverlay),
-bestHeaderHeight(0),
-bestHeaderDate(QDateTime()),
-layerIsVisible(false),
-userClosed(false),
-foreverHidden(false)
+ModalOverlay::ModalOverlay(bool enable_wallet, QWidget* parent)
+    : QWidget(parent),
+      ui(new Ui::ModalOverlay),
+      bestHeaderDate(QDateTime())
 {
     ui->setupUi(this);
 
diff --git a/src/qt/modaloverlay.h b/src/qt/modaloverlay.h
index 8b2403c8b15a..aed94f140cc8 100644
--- a/src/qt/modaloverlay.h
+++ b/src/qt/modaloverlay.h
@@ -43,12 +43,12 @@ public Q_SLOTS:
 
 private:
     Ui::ModalOverlay *ui;
-    int bestHeaderHeight; //best known height (based on the headers)
+    int bestHeaderHeight{0}; // best known height (based on the headers)
     QDateTime bestHeaderDate;
     QVector<QPair<qint64, double> > blockProcessTime;
-    bool layerIsVisible;
-    bool userClosed;
-    bool foreverHidden;
+    bool layerIsVisible{false};
+    bool userClosed{false};
+    bool foreverHidden{false};
     QPropertyAnimation m_animation;
     void UpdateHeaderSyncLabel();
 };
diff --git a/src/qt/notificator.cpp b/src/qt/notificator.cpp
index e9f666b506cc..211c5cf5f227 100644
--- a/src/qt/notificator.cpp
+++ b/src/qt/notificator.cpp
@@ -31,11 +31,7 @@ Notificator::Notificator(const QString &_programName, QSystemTrayIcon *_trayIcon
     QObject(_parent),
     parent(_parent),
     programName(_programName),
-    mode(None),
     trayIcon(_trayIcon)
-#ifdef USE_DBUS
-    ,interface(nullptr)
-#endif
 {
     if(_trayIcon && _trayIcon->supportsMessages())
     {
diff --git a/src/qt/notificator.h b/src/qt/notificator.h
index 97880469453b..c388159aca13 100644
--- a/src/qt/notificator.h
+++ b/src/qt/notificator.h
@@ -61,10 +61,10 @@ public Q_SLOTS:
         UserNotificationCenter      /**< Use the 10.8+ User Notification Center (Mac only) */
     };
     QString programName;
-    Mode mode;
+    Mode mode{None};
     QSystemTrayIcon *trayIcon;
 #ifdef USE_DBUS
-    QDBusInterface *interface;
+    QDBusInterface* interface{nullptr};
 
     void notifyDBus(Class cls, const QString &title, const QString &text, const QIcon &icon, int millisTimeout);
 #endif
diff --git a/src/qt/optionsdialog.cpp b/src/qt/optionsdialog.cpp
index 034ae4f908ef..5e9d38f5a892 100644
--- a/src/qt/optionsdialog.cpp
+++ b/src/qt/optionsdialog.cpp
@@ -39,13 +39,10 @@
 #include <QSystemTrayIcon>
 #include <QTimer>
 
-OptionsDialog::OptionsDialog(QWidget *parent, bool enableWallet) :
-    QDialog(parent, GUIUtil::dialog_flags),
-    ui(new Ui::OptionsDialog),
-    model(nullptr),
-    mapper(nullptr),
-    pageButtons(nullptr),
-    m_enable_wallet(enableWallet)
+OptionsDialog::OptionsDialog(QWidget* parent, bool enableWallet)
+    : QDialog(parent, GUIUtil::dialog_flags),
+      ui(new Ui::OptionsDialog),
+      m_enable_wallet(enableWallet)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/optionsdialog.h b/src/qt/optionsdialog.h
index 655d7ed6f6f2..13eb556f7c79 100644
--- a/src/qt/optionsdialog.h
+++ b/src/qt/optionsdialog.h
@@ -89,9 +89,9 @@ private Q_SLOTS:
 private:
     Ui::OptionsDialog *ui;
     ClientModel* m_client_model{nullptr};
-    OptionsModel *model;
-    QDataWidgetMapper *mapper;
-    QButtonGroup* pageButtons;
+    OptionsModel* model{nullptr};
+    QDataWidgetMapper* mapper{nullptr};
+    QButtonGroup* pageButtons{nullptr};
     QString previousTheme;
     AppearanceWidget* appearance;
     bool fCoinJoinEnabledPrev{false};
diff --git a/src/qt/overviewpage.cpp b/src/qt/overviewpage.cpp
index 8ed12617a19f..005893e79298 100644
--- a/src/qt/overviewpage.cpp
+++ b/src/qt/overviewpage.cpp
@@ -141,11 +141,7 @@ class TxViewDelegate : public QAbstractItemDelegate
 
 OverviewPage::OverviewPage(QWidget* parent) :
     QWidget(parent),
-    timer(nullptr),
     ui(new Ui::OverviewPage),
-    clientModel(nullptr),
-    walletModel(nullptr),
-    cachedNumISLocks(-1),
     txdelegate(new TxViewDelegate(this))
 {
     ui->setupUi(this);
diff --git a/src/qt/overviewpage.h b/src/qt/overviewpage.h
index 8c507e073e2a..7bbfae77c35b 100644
--- a/src/qt/overviewpage.h
+++ b/src/qt/overviewpage.h
@@ -49,15 +49,15 @@ public Q_SLOTS:
     void outOfSyncWarningClicked();
 
 private:
-    QTimer *timer;
+    QTimer* timer{nullptr};
     Ui::OverviewPage *ui;
-    ClientModel *clientModel;
-    WalletModel *walletModel;
+    ClientModel* clientModel{nullptr};
+    WalletModel* walletModel{nullptr};
     interfaces::WalletBalances m_balances;
     bool m_privacy{false};
     BitcoinUnit m_display_bitcoin_unit;
     bool fShowAdvancedCJUI;
-    int cachedNumISLocks;
+    int cachedNumISLocks{-1};
 
     TxViewDelegate *txdelegate;
     std::unique_ptr<TransactionFilterProxy> filter;
diff --git a/src/qt/paymentserver.cpp b/src/qt/paymentserver.cpp
index 6adf7fe4cc9b..a14ffd2909b0 100644
--- a/src/qt/paymentserver.cpp
+++ b/src/qt/paymentserver.cpp
@@ -125,11 +125,8 @@ bool PaymentServer::ipcSendCommandLine()
     return fResult;
 }
 
-PaymentServer::PaymentServer(QObject* parent, bool startLocalServer) :
-    QObject(parent),
-    saveURIs(true),
-    uriServer(nullptr),
-    optionsModel(nullptr)
+PaymentServer::PaymentServer(QObject* parent, bool startLocalServer)
+    : QObject(parent)
 {
     // Install global event filter to catch QFileOpenEvents
     // on Mac: sent when you click dash: links
diff --git a/src/qt/paymentserver.h b/src/qt/paymentserver.h
index 545007ae7b97..ca9bb8954f75 100644
--- a/src/qt/paymentserver.h
+++ b/src/qt/paymentserver.h
@@ -101,9 +101,9 @@ private Q_SLOTS:
     bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
-    bool saveURIs;                      // true during startup
-    QLocalServer* uriServer;
-    OptionsModel *optionsModel;
+    bool saveURIs{true}; // true during startup
+    QLocalServer* uriServer{nullptr};
+    OptionsModel* optionsModel{nullptr};
 };
 
 #endif // BITCOIN_QT_PAYMENTSERVER_H
diff --git a/src/qt/peertablemodel.cpp b/src/qt/peertablemodel.cpp
index 370f40e9931e..550cc2faaa54 100644
--- a/src/qt/peertablemodel.cpp
+++ b/src/qt/peertablemodel.cpp
@@ -13,10 +13,9 @@
 
 #include <QTimer>
 
-PeerTableModel::PeerTableModel(interfaces::Node& node, QObject* parent) :
-    QAbstractTableModel(parent),
-    m_node(node),
-    timer(nullptr)
+PeerTableModel::PeerTableModel(interfaces::Node& node, QObject* parent)
+    : QAbstractTableModel(parent),
+      m_node(node)
 {
     // set up timer for auto refresh
     timer = new QTimer(this);
diff --git a/src/qt/peertablemodel.h b/src/qt/peertablemodel.h
index e2515de7754f..9cbdad4374e2 100644
--- a/src/qt/peertablemodel.h
+++ b/src/qt/peertablemodel.h
@@ -110,7 +110,7 @@ public Q_SLOTS:
         /*: Title of Peers Table column which contains the peer's
             User Agent string. */
         tr("User Agent")};
-    QTimer *timer;
+    QTimer* timer{nullptr};
 };
 
 #endif // BITCOIN_QT_PEERTABLEMODEL_H
diff --git a/src/qt/qrdialog.h b/src/qt/qrdialog.h
index 681925377d5e..88ddaf5b1808 100644
--- a/src/qt/qrdialog.h
+++ b/src/qt/qrdialog.h
@@ -22,7 +22,7 @@ class QRDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit QRDialog(QWidget *parent = 0);
+    explicit QRDialog(QWidget* parent = nullptr);
     ~QRDialog();
 
     void setInfo(QString strWindowtitle, QString strQRCode, QString strTextInfo, QString strQRCodeTitle);
diff --git a/src/qt/qrimagewidget.cpp b/src/qt/qrimagewidget.cpp
index 967838dda79f..3d937bf7f680 100644
--- a/src/qt/qrimagewidget.cpp
+++ b/src/qt/qrimagewidget.cpp
@@ -23,8 +23,8 @@
 #include <qrencode.h>
 #endif
 
-QRImageWidget::QRImageWidget(QWidget *parent):
-    QLabel(parent), contextMenu(nullptr)
+QRImageWidget::QRImageWidget(QWidget* parent)
+    : QLabel(parent)
 {
     contextMenu = new QMenu(this);
     contextMenu->addAction(tr("&Save Image…"), this, &QRImageWidget::saveImage);
diff --git a/src/qt/qrimagewidget.h b/src/qt/qrimagewidget.h
index 776a920cc1cf..48c5a135ba1e 100644
--- a/src/qt/qrimagewidget.h
+++ b/src/qt/qrimagewidget.h
@@ -40,7 +40,7 @@ public Q_SLOTS:
     virtual void contextMenuEvent(QContextMenuEvent *event) override;
 
 private:
-    QMenu *contextMenu;
+    QMenu* contextMenu{nullptr};
 };
 
 #endif // BITCOIN_QT_QRIMAGEWIDGET_H
diff --git a/src/qt/qvalidatedlineedit.cpp b/src/qt/qvalidatedlineedit.cpp
index e66e8a5d328d..3ad2139ad3dc 100644
--- a/src/qt/qvalidatedlineedit.cpp
+++ b/src/qt/qvalidatedlineedit.cpp
@@ -6,10 +6,8 @@
 
 #include <qt/guiutil.h>
 
-QValidatedLineEdit::QValidatedLineEdit(QWidget *parent) :
-    QLineEdit(parent),
-    valid(true),
-    checkValidator(nullptr)
+QValidatedLineEdit::QValidatedLineEdit(QWidget* parent)
+    : QLineEdit(parent)
 {
     connect(this, &QValidatedLineEdit::textChanged, this, &QValidatedLineEdit::markValid);
 }
diff --git a/src/qt/qvalidatedlineedit.h b/src/qt/qvalidatedlineedit.h
index 12d35aa2645c..b26e2020c534 100644
--- a/src/qt/qvalidatedlineedit.h
+++ b/src/qt/qvalidatedlineedit.h
@@ -25,8 +25,8 @@ class QValidatedLineEdit : public QLineEdit
     void focusOutEvent(QFocusEvent *evt) override;
 
 private:
-    bool valid;
-    const QValidator *checkValidator;
+    bool valid{true};
+    const QValidator* checkValidator{nullptr};
 
 public Q_SLOTS:
     void setText(const QString&);
diff --git a/src/qt/qvaluecombobox.cpp b/src/qt/qvaluecombobox.cpp
index f94486a2f38f..c163ba56dca4 100644
--- a/src/qt/qvaluecombobox.cpp
+++ b/src/qt/qvaluecombobox.cpp
@@ -4,8 +4,8 @@
 
 #include <qt/qvaluecombobox.h>
 
-QValueComboBox::QValueComboBox(QWidget *parent) :
-        QComboBox(parent), role(Qt::UserRole)
+QValueComboBox::QValueComboBox(QWidget* parent)
+    : QComboBox(parent)
 {
     connect(this, qOverload<int>(&QComboBox::currentIndexChanged), this, &QValueComboBox::handleSelectionChanged);
 }
diff --git a/src/qt/qvaluecombobox.h b/src/qt/qvaluecombobox.h
index bde9c0d1a602..14379dd612b7 100644
--- a/src/qt/qvaluecombobox.h
+++ b/src/qt/qvaluecombobox.h
@@ -28,7 +28,7 @@ class QValueComboBox : public QComboBox
     void valueChanged();
 
 private:
-    int role;
+    int role{Qt::UserRole};
 
 private Q_SLOTS:
     void handleSelectionChanged(int idx);
diff --git a/src/qt/receivecoinsdialog.cpp b/src/qt/receivecoinsdialog.cpp
index ebb0798ed461..0e030606fd37 100644
--- a/src/qt/receivecoinsdialog.cpp
+++ b/src/qt/receivecoinsdialog.cpp
@@ -18,8 +18,7 @@
 
 ReceiveCoinsDialog::ReceiveCoinsDialog(QWidget* parent) :
     QDialog(parent, GUIUtil::dialog_flags),
-    ui(new Ui::ReceiveCoinsDialog),
-    model(nullptr)
+    ui(new Ui::ReceiveCoinsDialog)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/receivecoinsdialog.h b/src/qt/receivecoinsdialog.h
index 697c5f72b930..d0f29c86ffd4 100644
--- a/src/qt/receivecoinsdialog.h
+++ b/src/qt/receivecoinsdialog.h
@@ -47,7 +47,7 @@ public Q_SLOTS:
 
 private:
     Ui::ReceiveCoinsDialog *ui;
-    WalletModel *model;
+    WalletModel* model{nullptr};
     QMenu *contextMenu;
     QAction* copyLabelAction;
     QAction* copyMessageAction;
diff --git a/src/qt/receiverequestdialog.cpp b/src/qt/receiverequestdialog.cpp
index 84021eb2a9ba..dee027526167 100644
--- a/src/qt/receiverequestdialog.cpp
+++ b/src/qt/receiverequestdialog.cpp
@@ -19,10 +19,9 @@
 #include <config/bitcoin-config.h> /* for USE_QRCODE */
 #endif
 
-ReceiveRequestDialog::ReceiveRequestDialog(QWidget *parent) :
-    QDialog(parent, GUIUtil::dialog_flags),
-    ui(new Ui::ReceiveRequestDialog),
-    model(nullptr)
+ReceiveRequestDialog::ReceiveRequestDialog(QWidget* parent)
+    : QDialog(parent, GUIUtil::dialog_flags),
+      ui(new Ui::ReceiveRequestDialog)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/receiverequestdialog.h b/src/qt/receiverequestdialog.h
index c861680761e3..d64fee366360 100644
--- a/src/qt/receiverequestdialog.h
+++ b/src/qt/receiverequestdialog.h
@@ -33,7 +33,7 @@ private Q_SLOTS:
 
 private:
     Ui::ReceiveRequestDialog *ui;
-    WalletModel *model;
+    WalletModel* model{nullptr};
     SendCoinsRecipient info;
 };
 
diff --git a/src/qt/recentrequeststablemodel.h b/src/qt/recentrequeststablemodel.h
index 1cc8c2b2b506..0a38b57de024 100644
--- a/src/qt/recentrequeststablemodel.h
+++ b/src/qt/recentrequeststablemodel.h
@@ -18,11 +18,11 @@ class WalletModel;
 class RecentRequestEntry
 {
 public:
-    RecentRequestEntry() : nVersion(RecentRequestEntry::CURRENT_VERSION), id(0) { }
+    RecentRequestEntry() : nVersion(RecentRequestEntry::CURRENT_VERSION) {}
 
     static const int CURRENT_VERSION = 1;
     int nVersion;
-    int64_t id;
+    int64_t id{0};
     QDateTime date;
     SendCoinsRecipient recipient;
 
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index b5e6e81ffdde..2bf5ca1d603f 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -63,11 +63,7 @@ int getIndexForConfTarget(int target) {
 SendCoinsDialog::SendCoinsDialog(bool _fCoinJoin, QWidget* parent) :
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::SendCoinsDialog),
-    clientModel(nullptr),
-    model(nullptr),
-    m_coin_control(new CCoinControl),
-    fNewRecipientAllowed(true),
-    fFeeMinimized(true)
+    m_coin_control(new CCoinControl)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/sendcoinsdialog.h b/src/qt/sendcoinsdialog.h
index 22aa578be639..d9d5857a9dcb 100644
--- a/src/qt/sendcoinsdialog.h
+++ b/src/qt/sendcoinsdialog.h
@@ -63,13 +63,13 @@ public Q_SLOTS:
 
 private:
     Ui::SendCoinsDialog *ui;
-    ClientModel *clientModel;
-    WalletModel *model;
+    ClientModel* clientModel{nullptr};
+    WalletModel* model{nullptr};
     std::unique_ptr<wallet::CCoinControl> m_coin_control;
     std::unique_ptr<WalletModelTransaction> m_current_transaction;
-    bool fNewRecipientAllowed;
+    bool fNewRecipientAllowed{true};
     bool send(const QList<SendCoinsRecipient>& recipients, QString& question_string, QString& informative_text, QString& detailed_text);
-    bool fFeeMinimized;
+    bool fFeeMinimized{true};
     bool fKeepChangeAddress;
 
     // Process WalletModel::SendCoinsReturn and generate a pair consisting
diff --git a/src/qt/sendcoinsentry.cpp b/src/qt/sendcoinsentry.cpp
index fb447acc362d..0fe12ebad5dc 100644
--- a/src/qt/sendcoinsentry.cpp
+++ b/src/qt/sendcoinsentry.cpp
@@ -22,8 +22,7 @@
 
 SendCoinsEntry::SendCoinsEntry(QWidget* parent) :
     QWidget(parent),
-    ui(new Ui::SendCoinsEntry),
-    model(nullptr)
+    ui(new Ui::SendCoinsEntry)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/sendcoinsentry.h b/src/qt/sendcoinsentry.h
index 87b931e68e75..1cbd0637e8f5 100644
--- a/src/qt/sendcoinsentry.h
+++ b/src/qt/sendcoinsentry.h
@@ -72,7 +72,7 @@ private Q_SLOTS:
 private:
     SendCoinsRecipient recipient;
     Ui::SendCoinsEntry *ui;
-    WalletModel *model;
+    WalletModel* model{nullptr};
 
     /** Set required icons for buttons inside the dialog */
     void setButtonIcons();
diff --git a/src/qt/signverifymessagedialog.cpp b/src/qt/signverifymessagedialog.cpp
index 058c6f454862..c66d8478a5c8 100644
--- a/src/qt/signverifymessagedialog.cpp
+++ b/src/qt/signverifymessagedialog.cpp
@@ -23,9 +23,7 @@
 
 SignVerifyMessageDialog::SignVerifyMessageDialog(QWidget* parent) :
     QDialog(parent, GUIUtil::dialog_flags),
-    ui(new Ui::SignVerifyMessageDialog),
-    model(nullptr),
-    pageButtons(nullptr)
+    ui(new Ui::SignVerifyMessageDialog)
 {
     ui->setupUi(this);
 
diff --git a/src/qt/signverifymessagedialog.h b/src/qt/signverifymessagedialog.h
index 6ee22dde157f..04bb39e0c915 100644
--- a/src/qt/signverifymessagedialog.h
+++ b/src/qt/signverifymessagedialog.h
@@ -37,8 +37,8 @@ class SignVerifyMessageDialog : public QDialog
 
 private:
     Ui::SignVerifyMessageDialog *ui;
-    WalletModel *model;
-    QButtonGroup* pageButtons;
+    WalletModel* model{nullptr};
+    QButtonGroup* pageButtons{nullptr};
 
     void showEvent(QShowEvent* event) override;
 
diff --git a/src/qt/splashscreen.cpp b/src/qt/splashscreen.cpp
index 3aa8454664b1..f9b32dc58e01 100644
--- a/src/qt/splashscreen.cpp
+++ b/src/qt/splashscreen.cpp
@@ -29,8 +29,9 @@
 #include <QPainter>
 #include <QScreen>
 
-SplashScreen::SplashScreen(const NetworkStyle *networkStyle) :
-    QWidget(), curAlignment(0)
+
+SplashScreen::SplashScreen(const NetworkStyle* networkStyle)
+    : QWidget()
 {
 
     // transparent background
diff --git a/src/qt/splashscreen.h b/src/qt/splashscreen.h
index af619b37ac69..d326bceea920 100644
--- a/src/qt/splashscreen.h
+++ b/src/qt/splashscreen.h
@@ -57,7 +57,7 @@ public Q_SLOTS:
     QPixmap pixmap;
     QString curMessage;
     QColor curColor;
-    int curAlignment;
+    int curAlignment{0};
 
     interfaces::Node* m_node = nullptr;
     bool m_shutdown = false;
diff --git a/src/qt/trafficgraphdata.cpp b/src/qt/trafficgraphdata.cpp
index 7561336d6a10..2de10a90127e 100644
--- a/src/qt/trafficgraphdata.cpp
+++ b/src/qt/trafficgraphdata.cpp
@@ -23,10 +23,7 @@ const int TrafficGraphData::SMALLEST_SAMPLE_PERIOD =
         TrafficGraphData::RangeMinutes[TrafficGraphData::Range_5m] * 60 * 1000 / TrafficGraphData::DESIRED_DATA_SAMPLES;
 
 TrafficGraphData::TrafficGraphData(GraphRange range)
-    :currentGraphRange(range),
-    currentSampleCounter(0),
-    nLastBytesIn(0),
-    nLastBytesOut(0)
+    :currentGraphRange(range)
 {
 }
 
diff --git a/src/qt/trafficgraphdata.h b/src/qt/trafficgraphdata.h
index 1847bd5b4def..a9e1ccfadfd1 100644
--- a/src/qt/trafficgraphdata.h
+++ b/src/qt/trafficgraphdata.h
@@ -75,10 +75,10 @@ class TrafficGraphData
     SampleQueueMap sampleStash;
 
     GraphRange currentGraphRange;
-    int currentSampleCounter;
+    int currentSampleCounter{0};
 
-    quint64 nLastBytesIn;
-    quint64 nLastBytesOut;
+    quint64 nLastBytesIn{0};
+    quint64 nLastBytesOut{0};
 
     void update(GraphRange range, const TrafficSample &trafficSample);
 
diff --git a/src/qt/trafficgraphwidget.cpp b/src/qt/trafficgraphwidget.cpp
index fa3af19bf872..265bb669ed57 100644
--- a/src/qt/trafficgraphwidget.cpp
+++ b/src/qt/trafficgraphwidget.cpp
@@ -18,15 +18,9 @@
 #define XMARGIN                 10
 #define YMARGIN                 10
 
-#define DEFAULT_SAMPLE_HEIGHT    1.1f
-
-TrafficGraphWidget::TrafficGraphWidget(QWidget *parent) :
-    QWidget(parent),
-    timer(nullptr),
-    fMax(DEFAULT_SAMPLE_HEIGHT),
-    nMins(0),
-    clientModel(nullptr),
-    trafficGraphData(TrafficGraphData::Range_30m)
+TrafficGraphWidget::TrafficGraphWidget(QWidget* parent)
+    : QWidget(parent),
+      trafficGraphData(TrafficGraphData::Range_30m)
 {
     timer = new QTimer(this);
     connect(timer, &QTimer::timeout, this, &TrafficGraphWidget::updateRates);
@@ -234,7 +228,7 @@ void TrafficGraphWidget::updateRates()
     bool updated = trafficGraphData.update(clientModel->node().getTotalBytesRecv(),clientModel->node().getTotalBytesSent());
 
     if (updated){
-        float tmax = DEFAULT_SAMPLE_HEIGHT;
+        float tmax = default_sample_height;
         for (const TrafficSample& sample : trafficGraphData.getCurrentRangeQueueWithAverageBandwidth()) {
             if(sample.in > tmax) tmax = sample.in;
             if(sample.out > tmax) tmax = sample.out;
@@ -253,7 +247,7 @@ void TrafficGraphWidget::setGraphRangeMins(int value)
 void TrafficGraphWidget::clear()
 {
     trafficGraphData.clear();
-    fMax = DEFAULT_SAMPLE_HEIGHT;
+    fMax = default_sample_height;
     if(clientModel) {
         trafficGraphData.setLastBytes(clientModel->node().getTotalBytesRecv(), clientModel->node().getTotalBytesSent());
     }
diff --git a/src/qt/trafficgraphwidget.h b/src/qt/trafficgraphwidget.h
index e3e57620f761..6fc60c0d556c 100644
--- a/src/qt/trafficgraphwidget.h
+++ b/src/qt/trafficgraphwidget.h
@@ -34,13 +34,14 @@ public Q_SLOTS:
     void clear();
 
 private:
+    static constexpr float default_sample_height{1.1f};
     typedef std::function<float(const TrafficSample&)> SampleChooser;
     void paintPath(QPainterPath &path, const TrafficGraphData::SampleQueue &queue, SampleChooser chooser);
 
-    QTimer *timer;
-    float fMax;
-    int nMins;
-    ClientModel *clientModel;
+    QTimer* timer{nullptr};
+    float fMax{default_sample_height};
+    int nMins{0};
+    ClientModel* clientModel{nullptr};
     TrafficGraphData trafficGraphData;
 };
 
diff --git a/src/qt/transactionfilterproxy.cpp b/src/qt/transactionfilterproxy.cpp
index f14f0a71628f..12758886ad63 100644
--- a/src/qt/transactionfilterproxy.cpp
+++ b/src/qt/transactionfilterproxy.cpp
@@ -11,14 +11,10 @@
 #include <cstdlib>
 #include <optional>
 
-TransactionFilterProxy::TransactionFilterProxy(QObject *parent) :
-    QSortFilterProxyModel(parent),
-    m_search_string(),
-    typeFilter(COMMON_TYPES),
-    watchOnlyFilter(WatchOnlyFilter_All),
-    minAmount(0),
-    limitRows(-1),
-    showInactive(true)
+TransactionFilterProxy::TransactionFilterProxy(QObject* parent)
+    : QSortFilterProxyModel(parent),
+      m_search_string(),
+      typeFilter(COMMON_TYPES)
 {
 }
 
diff --git a/src/qt/transactionfilterproxy.h b/src/qt/transactionfilterproxy.h
index 71d6f031a364..1801d27bcae8 100644
--- a/src/qt/transactionfilterproxy.h
+++ b/src/qt/transactionfilterproxy.h
@@ -60,10 +60,10 @@ class TransactionFilterProxy : public QSortFilterProxyModel
     std::optional<QDateTime> dateTo;
     QString m_search_string;
     quint32 typeFilter;
-    WatchOnlyFilter watchOnlyFilter;
-    CAmount minAmount;
-    int limitRows;
-    bool showInactive;
+    WatchOnlyFilter watchOnlyFilter{WatchOnlyFilter_All};
+    CAmount minAmount{0};
+    int limitRows{-1};
+    bool showInactive{true};
 };
 
 #endif // BITCOIN_QT_TRANSACTIONFILTERPROXY_H
diff --git a/src/qt/transactiontablemodel.cpp b/src/qt/transactiontablemodel.cpp
index 296a9e88622d..e676f04a2237 100644
--- a/src/qt/transactiontablemodel.cpp
+++ b/src/qt/transactiontablemodel.cpp
@@ -268,9 +268,7 @@ class TransactionTablePriv
 TransactionTableModel::TransactionTableModel(WalletModel *parent):
         QAbstractTableModel(parent),
         walletModel(parent),
-        priv(new TransactionTablePriv(this)),
-        fProcessingQueuedTransactions(false),
-        cachedChainLockHeight(-1)
+        priv(new TransactionTablePriv(this))
 {
     subscribeToCoreSignals();
 
diff --git a/src/qt/transactiontablemodel.h b/src/qt/transactiontablemodel.h
index 630fec039f73..c1fb9a447585 100644
--- a/src/qt/transactiontablemodel.h
+++ b/src/qt/transactiontablemodel.h
@@ -93,8 +93,8 @@ class TransactionTableModel : public QAbstractTableModel
     std::unique_ptr<interfaces::Handler> m_handler_show_progress;
     QStringList columns;
     TransactionTablePriv *priv;
-    bool fProcessingQueuedTransactions;
-    int cachedChainLockHeight;
+    bool fProcessingQueuedTransactions{false};
+    int cachedChainLockHeight{-1};
 
     void subscribeToCoreSignals();
     void unsubscribeFromCoreSignals();
diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
index 0a9a196cfc04..d6cddd67dbae 100644
--- a/src/qt/walletmodel.cpp
+++ b/src/qt/walletmodel.cpp
@@ -50,13 +50,7 @@ WalletModel::WalletModel(std::unique_ptr<interfaces::Wallet> wallet, ClientModel
     m_client_model(&client_model),
     m_node(client_model.node()),
     optionsModel(client_model.getOptionsModel()),
-    addressTableModel(nullptr),
-    transactionTableModel(nullptr),
-    recentRequestsTableModel(nullptr),
-    cachedEncryptionStatus(Unencrypted),
-    timer(new QTimer(this)),
-    cachedNumISLocks(0),
-    cachedCoinJoinRounds(0)
+    timer(new QTimer(this))
 {
     fHaveWatchOnly = m_wallet->haveWatchOnly();
     addressTableModel = new AddressTableModel(this);
diff --git a/src/qt/walletmodel.h b/src/qt/walletmodel.h
index b33e74a43ada..3124f86c110a 100644
--- a/src/qt/walletmodel.h
+++ b/src/qt/walletmodel.h
@@ -183,16 +183,16 @@ class WalletModel : public QObject
     // (transaction fee, for example)
     OptionsModel *optionsModel;
 
-    AddressTableModel *addressTableModel;
-    TransactionTableModel *transactionTableModel;
-    RecentRequestsTableModel *recentRequestsTableModel;
+    AddressTableModel* addressTableModel{nullptr};
+    TransactionTableModel* transactionTableModel{nullptr};
+    RecentRequestsTableModel* recentRequestsTableModel{nullptr};
 
     // Cache some values to be able to detect changes
     interfaces::WalletBalances m_cached_balances;
-    EncryptionStatus cachedEncryptionStatus;
+    EncryptionStatus cachedEncryptionStatus{Unencrypted};
     QTimer* timer;
-    int cachedNumISLocks;
-    int cachedCoinJoinRounds;
+    int cachedNumISLocks{0};
+    int cachedCoinJoinRounds{0};
 
     // Block hash denoting when the last balance update was done.
     uint256 m_cached_last_update_tip{};
diff --git a/src/qt/walletmodeltransaction.cpp b/src/qt/walletmodeltransaction.cpp
index c3dc38fa27c9..496cc7f10ff6 100644
--- a/src/qt/walletmodeltransaction.cpp
+++ b/src/qt/walletmodeltransaction.cpp
@@ -10,9 +10,8 @@
 
 #include <key_io.h>
 
-WalletModelTransaction::WalletModelTransaction(const QList<SendCoinsRecipient> &_recipients) :
-    recipients(_recipients),
-    fee(0)
+WalletModelTransaction::WalletModelTransaction(const QList<SendCoinsRecipient>& _recipients)
+    : recipients(_recipients)
 {
 }
 
diff --git a/src/qt/walletmodeltransaction.h b/src/qt/walletmodeltransaction.h
index 67effb8e2908..61e1fc76ee41 100644
--- a/src/qt/walletmodeltransaction.h
+++ b/src/qt/walletmodeltransaction.h
@@ -41,7 +41,7 @@ class WalletModelTransaction
 private:
     QList<SendCoinsRecipient> recipients;
     CTransactionRef wtx;
-    CAmount fee;
+    CAmount fee{0};
 };
 
 #endif // BITCOIN_QT_WALLETMODELTRANSACTION_H
diff --git a/src/qt/walletview.cpp b/src/qt/walletview.cpp
index e74ecd52ec44..684ab37e8bf4 100644
--- a/src/qt/walletview.cpp
+++ b/src/qt/walletview.cpp
@@ -37,7 +37,6 @@
 
 WalletView::WalletView(WalletModel* wallet_model, QWidget* parent)
     : QStackedWidget(parent),
-      clientModel(nullptr),
       walletModel(wallet_model)
 {
     assert(walletModel);
diff --git a/src/qt/walletview.h b/src/qt/walletview.h
index 328b42821d06..4a527fbfb9bc 100644
--- a/src/qt/walletview.h
+++ b/src/qt/walletview.h
@@ -52,7 +52,7 @@ class WalletView : public QStackedWidget
     void showOutOfSyncWarning(bool fShow);
 
 private:
-    ClientModel *clientModel;
+    ClientModel* clientModel{nullptr};
 
     //!
     //! The wallet model represents a bitcoin wallet, and offers access to
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index 0ef7c2bd30e6..f84cb6794fbe 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -17,7 +17,7 @@
 #include <optional>
 #include <vector>
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 class CBlock;
 class CBlockIndex;
diff --git a/src/rpc/index_util.h b/src/rpc/index_util.h
index 2624ae4578bd..1a351f8f37dc 100644
--- a/src/rpc/index_util.h
+++ b/src/rpc/index_util.h
@@ -22,7 +22,7 @@ class uint256;
 
 enum class AddressType : uint8_t;
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 //! throws JSONRPCError if address index is unavailable
 bool GetAddressIndex(CBlockTreeDB& block_tree_db, const uint160& addressHash, const AddressType type,
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index 9aae2d7e0c96..67d012ab2bcd 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -359,6 +359,7 @@ struct Sections {
         const auto indent = std::string(current_indent, ' ');
         const auto indent_next = std::string(current_indent + 2, ' ');
         const bool push_name{outer_type == OuterType::OBJ}; // Dictionary keys must have a name
+        const bool is_top_level_arg{outer_type == OuterType::NONE}; // True on the first recursion
 
         switch (arg.m_type) {
         case RPCArg::Type::STR_HEX:
@@ -367,7 +368,7 @@ struct Sections {
         case RPCArg::Type::AMOUNT:
         case RPCArg::Type::RANGE:
         case RPCArg::Type::BOOL: {
-            if (outer_type == OuterType::NONE) return; // Nothing more to do for non-recursive types on first recursion
+            if (is_top_level_arg) return; // Nothing more to do for non-recursive types on first recursion
             auto left = indent;
             if (arg.m_type_str.size() != 0 && push_name) {
                 left += "\"" + arg.GetName() + "\": " + arg.m_type_str.at(0);
@@ -375,12 +376,12 @@ struct Sections {
                 left += push_name ? arg.ToStringObj(/*oneline=*/false) : arg.ToString(/*oneline=*/false);
             }
             left += ",";
-            PushSection({left, arg.ToDescriptionString()});
+            PushSection({left, arg.ToDescriptionString(/*is_named_arg=*/push_name)});
             break;
         }
         case RPCArg::Type::OBJ:
         case RPCArg::Type::OBJ_USER_KEYS: {
-            const auto right = outer_type == OuterType::NONE ? "" : arg.ToDescriptionString();
+            const auto right = is_top_level_arg ? "" : arg.ToDescriptionString(/*is_named_arg=*/push_name);
             PushSection({indent + (push_name ? "\"" + arg.GetName() + "\": " : "") + "{", right});
             for (const auto& arg_inner : arg.m_inner) {
                 Push(arg_inner, current_indent + 2, OuterType::OBJ);
@@ -388,20 +389,20 @@ struct Sections {
             if (arg.m_type != RPCArg::Type::OBJ) {
                 PushSection({indent_next + "...", ""});
             }
-            PushSection({indent + "}" + (outer_type != OuterType::NONE ? "," : ""), ""});
+            PushSection({indent + "}" + (is_top_level_arg ? "" : ","), ""});
             break;
         }
         case RPCArg::Type::ARR: {
             auto left = indent;
             left += push_name ? "\"" + arg.GetName() + "\": " : "";
             left += "[";
-            const auto right = outer_type == OuterType::NONE ? "" : arg.ToDescriptionString();
+            const auto right = is_top_level_arg ? "" : arg.ToDescriptionString(/*is_named_arg=*/push_name);
             PushSection({left, right});
             for (const auto& arg_inner : arg.m_inner) {
                 Push(arg_inner, current_indent + 2, OuterType::ARR);
             }
             PushSection({indent_next + "...", ""});
-            PushSection({indent + "]" + (outer_type != OuterType::NONE ? "," : ""), ""});
+            PushSection({indent + "]" + (is_top_level_arg ? "" : ","), ""});
             break;
         }
         } // no default case, so the compiler can warn about missing cases
@@ -595,7 +596,7 @@ std::string RPCHelpMan::ToString() const
         if (i == 0) ret += "\nArguments:\n";
 
         // Push named argument name and description
-        sections.m_sections.emplace_back(::ToString(i + 1) + ". " + arg.GetFirstName(), arg.ToDescriptionString());
+        sections.m_sections.emplace_back(::ToString(i + 1) + ". " + arg.GetFirstName(), arg.ToDescriptionString(/*is_named_arg=*/true));
         sections.m_max_pad = std::max(sections.m_max_pad, sections.m_sections.back().m_left.size());
 
         // Recursively push nested args
@@ -651,7 +652,7 @@ bool RPCArg::IsOptional() const
     }
 }
 
-std::string RPCArg::ToDescriptionString() const
+std::string RPCArg::ToDescriptionString(bool is_named_arg) const
 {
     std::string ret;
     ret += "(";
@@ -697,14 +698,12 @@ std::string RPCArg::ToDescriptionString() const
         ret += ", optional, default=" + std::get<RPCArg::Default>(m_fallback).write();
     } else {
         switch (std::get<RPCArg::Optional>(m_fallback)) {
+        case RPCArg::Optional::OMITTED_NAMED_ARG: // Deprecated alias for OMITTED, can be removed
         case RPCArg::Optional::OMITTED: {
+            if (is_named_arg) ret += ", optional"; // Default value is "null" in dicts. Otherwise,
             // nothing to do. Element is treated as if not present and has no default value
             break;
         }
-        case RPCArg::Optional::OMITTED_NAMED_ARG: {
-            ret += ", optional"; // Default value is "null"
-            break;
-        }
         case RPCArg::Optional::NO: {
             ret += ", required";
             break;
diff --git a/src/rpc/util.h b/src/rpc/util.h
index fe12b4cbaf4f..6a62ca00e3e2 100644
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -157,21 +157,25 @@ struct RPCArg {
         /** Required arg */
         NO,
         /**
+         * The arg is optional for one of two reasons:
+         *
          * Optional arg that is a named argument and has a default value of
-         * `null`. When possible, the default value should be specified.
-         */
-        OMITTED_NAMED_ARG,
-        /**
+         * `null`.
+         *
          * Optional argument with default value omitted because they are
-         * implicitly clear. That is, elements in an array or object may not
+         * implicitly clear. That is, elements in an array may not
          * exist by default.
          * When possible, the default value should be specified.
          */
         OMITTED,
+        OMITTED_NAMED_ARG, // Deprecated alias for OMITTED, can be removed
     };
+    /** Hint for default value */
     using DefaultHint = std::string;
+    /** Default constant value */
     using Default = UniValue;
-    using Fallback = std::variant<Optional, /* hint for default value */ DefaultHint, /* default constant value */ Default>;
+    using Fallback = std::variant<Optional, DefaultHint, Default>;
+
     const std::string m_names; //!< The name of the arg (can be empty for inner args, can contain multiple aliases separated by | for named request arguments)
     const Type m_type;
     const bool m_hidden;
@@ -182,13 +186,13 @@ struct RPCArg {
     const std::vector<std::string> m_type_str; //!< Should be empty unless it is supposed to override the auto-generated type strings. Vector length is either 0 or 2, m_type_str.at(0) will override the type of the value in a key-value pair, m_type_str.at(1) will override the type in the argument description.
 
     RPCArg(
-        const std::string name,
-        const Type type,
-        const Fallback fallback,
-        const std::string description,
-        const std::string oneline_description = "",
-        const std::vector<std::string> type_str = {},
-        const bool hidden = false)
+        std::string name,
+        Type type,
+        Fallback fallback,
+        std::string description,
+        std::string oneline_description = "",
+        std::vector<std::string> type_str = {},
+        bool hidden = false)
         : m_names{std::move(name)},
           m_type{std::move(type)},
           m_hidden{hidden},
@@ -201,13 +205,13 @@ struct RPCArg {
     }
 
     RPCArg(
-        const std::string name,
-        const Type type,
-        const Fallback fallback,
-        const std::string description,
-        const std::vector<RPCArg> inner,
-        const std::string oneline_description = "",
-        const std::vector<std::string> type_str = {})
+        std::string name,
+        Type type,
+        Fallback fallback,
+        std::string description,
+        std::vector<RPCArg> inner,
+        std::string oneline_description = "",
+        std::vector<std::string> type_str = {})
         : m_names{std::move(name)},
           m_type{std::move(type)},
           m_hidden{false},
@@ -242,7 +246,7 @@ struct RPCArg {
      * Return the description string, including the argument type and whether
      * the argument is required.
      */
-    std::string ToDescriptionString() const;
+    std::string ToDescriptionString(bool is_named_arg) const;
 };
 
 struct RPCResult {
@@ -270,12 +274,12 @@ struct RPCResult {
     const std::string m_cond;
 
     RPCResult(
-        const std::string cond,
-        const Type type,
-        const std::string m_key_name,
-        const bool optional,
-        const std::string description,
-        const std::vector<RPCResult> inner = {})
+        std::string cond,
+        Type type,
+        std::string m_key_name,
+        bool optional,
+        std::string description,
+        std::vector<RPCResult> inner = {})
         : m_type{std::move(type)},
           m_key_name{std::move(m_key_name)},
           m_inner{std::move(inner)},
@@ -288,19 +292,19 @@ struct RPCResult {
     }
 
     RPCResult(
-        const std::string cond,
-        const Type type,
-        const std::string m_key_name,
-        const std::string description,
-        const std::vector<RPCResult> inner = {})
-        : RPCResult{cond, type, m_key_name, false, description, inner} {}
+        std::string cond,
+        Type type,
+        std::string m_key_name,
+        std::string description,
+        std::vector<RPCResult> inner = {})
+        : RPCResult{std::move(cond), type, std::move(m_key_name), /*optional=*/false, std::move(description), std::move(inner)} {}
 
     RPCResult(
-        const Type type,
-        const std::string m_key_name,
-        const bool optional,
-        const std::string description,
-        const std::vector<RPCResult> inner = {})
+        Type type,
+        std::string m_key_name,
+        bool optional,
+        std::string description,
+        std::vector<RPCResult> inner = {})
         : m_type{std::move(type)},
           m_key_name{std::move(m_key_name)},
           m_inner{std::move(inner)},
@@ -312,10 +316,10 @@ struct RPCResult {
     }
 
     RPCResult(
-        const Type type,
-        const std::string m_key_name,
-        const std::string description,
-        const std::vector<RPCResult> inner = {})
+        Type type,
+        std::string m_key_name,
+        std::string description,
+        std::vector<RPCResult> inner = {})
         : RPCResult{type, m_key_name, false, description, inner} {}
 
     /** Append the sections of the result. */
diff --git a/src/serialize.h b/src/serialize.h
index d0ac4e8f8917..027f9d87c434 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -1347,11 +1347,11 @@ struct CSerActionUnserialize
 class CSizeComputer
 {
 protected:
-    size_t nSize;
+    size_t nSize{0};
 
     const int nVersion;
 public:
-    explicit CSizeComputer(int nVersionIn) : nSize(0), nVersion(nVersionIn) {}
+    explicit CSizeComputer(int nVersionIn) : nVersion(nVersionIn) {}
 
     void write(Span<const std::byte> src)
     {
diff --git a/src/span.h b/src/span.h
index 6e6b58dbaa0b..fd9cdbc9eec5 100644
--- a/src/span.h
+++ b/src/span.h
@@ -96,7 +96,7 @@ template<typename C>
 class Span
 {
     C* m_data;
-    std::size_t m_size;
+    std::size_t m_size{0};
 
     template <class T>
     struct is_Span_int : public std::false_type {};
@@ -107,7 +107,7 @@ class Span
 
 
 public:
-    constexpr Span() noexcept : m_data(nullptr), m_size(0) {}
+    constexpr Span() noexcept : m_data(nullptr) {}
 
     /** Construct a span from a begin pointer and a size.
      *
diff --git a/src/stats/client.h b/src/stats/client.h
index dad20111d9c7..a534fbea9b25 100644
--- a/src/stats/client.h
+++ b/src/stats/client.h
@@ -17,11 +17,11 @@
 class ArgsManager;
 
 /** Default host assumed to be running a Statsd server */
-static const std::string DEFAULT_STATSD_HOST{""};
+static const std::string DEFAULT_STATSD_HOST{};
 /** Default prefix prepended to Statsd message keys */
-static const std::string DEFAULT_STATSD_PREFIX{""};
+static const std::string DEFAULT_STATSD_PREFIX{};
 /** Default suffix appended to Statsd message keys */
-static const std::string DEFAULT_STATSD_SUFFIX{""};
+static const std::string DEFAULT_STATSD_SUFFIX{};
 
 /** Default number of milliseconds between flushing a queue of messages */
 static constexpr int DEFAULT_STATSD_DURATION{1000};
diff --git a/src/streams.h b/src/streams.h
index 9790914f47cd..150c420c789b 100644
--- a/src/streams.h
+++ b/src/streams.h
@@ -624,8 +624,8 @@ class CBufferedFile
     const int nVersion;
 
     FILE *src;            //!< source file
-    uint64_t nSrcPos;     //!< how many bytes have been read from source
-    uint64_t m_read_pos;    //!< how many bytes have been read from this
+    uint64_t nSrcPos{0};  //!< how many bytes have been read from source
+    uint64_t m_read_pos{0}; //!< how many bytes have been read from this
     uint64_t nReadLimit;  //!< up to which position we're allowed to read
     uint64_t nRewind;     //!< how many bytes we guarantee to rewind
     std::vector<std::byte> vchBuf; //!< the buffer
@@ -671,7 +671,7 @@ class CBufferedFile
 
 public:
     CBufferedFile(FILE* fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn)
-        : nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), m_read_pos(0), nReadLimit(std::numeric_limits<uint64_t>::max()), nRewind(nRewindIn), vchBuf(nBufSize, std::byte{0})
+        : nType(nTypeIn), nVersion(nVersionIn), nReadLimit(std::numeric_limits<uint64_t>::max()), nRewind(nRewindIn), vchBuf(nBufSize, std::byte{0})
     {
         if (nRewindIn >= nBufSize)
             throw std::ios_base::failure("Rewind limit must be less than buffer size");
diff --git a/src/support/allocators/mt_pooled_secure.h b/src/support/allocators/mt_pooled_secure.h
index c97c22d36cf1..7f4576715db0 100644
--- a/src/support/allocators/mt_pooled_secure.h
+++ b/src/support/allocators/mt_pooled_secure.h
@@ -38,7 +38,7 @@ struct mt_pooled_secure_allocator : public std::allocator<T> {
     }
     ~mt_pooled_secure_allocator() noexcept {}
 
-    T* allocate(std::size_t n, const void* hint = 0)
+    T* allocate(std::size_t n, const void* hint = nullptr)
     {
         size_t bucket = get_bucket();
         std::lock_guard<std::mutex> lock(pools[bucket]->mutex);
diff --git a/src/support/allocators/pooled_secure.h b/src/support/allocators/pooled_secure.h
index 3e8252a23065..f24707c31f0e 100644
--- a/src/support/allocators/pooled_secure.h
+++ b/src/support/allocators/pooled_secure.h
@@ -32,7 +32,7 @@ struct pooled_secure_allocator : public std::allocator<T> {
                             pool(nrequested_size, nnext_size, nmax_size){}
     ~pooled_secure_allocator() noexcept {}
 
-    T* allocate(std::size_t n, const void* hint = 0)
+    T* allocate(std::size_t n, const void* hint = nullptr)
     {
         size_t chunks = (n * sizeof(T) + pool.get_requested_size() - 1) / pool.get_requested_size();
         return static_cast<T*>(pool.ordered_malloc(chunks));
diff --git a/src/support/lockedpool.cpp b/src/support/lockedpool.cpp
index 5682211630a3..6c3aaa9f04fa 100644
--- a/src/support/lockedpool.cpp
+++ b/src/support/lockedpool.cpp
@@ -281,8 +281,8 @@ size_t PosixLockedPageAllocator::GetLimit()
 /*******************************************************************************/
 // Implementation: LockedPool
 
-LockedPool::LockedPool(std::unique_ptr<LockedPageAllocator> allocator_in, LockingFailed_Callback lf_cb_in):
-    allocator(std::move(allocator_in)), lf_cb(lf_cb_in), cumulative_bytes_locked(0)
+LockedPool::LockedPool(std::unique_ptr<LockedPageAllocator> allocator_in, LockingFailed_Callback lf_cb_in)
+    : allocator(std::move(allocator_in)), lf_cb(lf_cb_in)
 {
 }
 
diff --git a/src/support/lockedpool.h b/src/support/lockedpool.h
index 794e51cc6baa..81e0df513a33 100644
--- a/src/support/lockedpool.h
+++ b/src/support/lockedpool.h
@@ -198,7 +198,7 @@ class LockedPool
 
     std::list<LockedPageArena> arenas;
     LockingFailed_Callback lf_cb;
-    size_t cumulative_bytes_locked;
+    size_t cumulative_bytes_locked{0};
     /** Mutex protects access to this pool's data structures, including arenas.
      */
     mutable std::mutex mutex;
diff --git a/src/test/fuzz/miniscript.cpp b/src/test/fuzz/miniscript.cpp
index 591cbc77118f..592ee2e560fb 100644
--- a/src/test/fuzz/miniscript.cpp
+++ b/src/test/fuzz/miniscript.cpp
@@ -104,7 +104,7 @@ struct ScriptParserContext {
         return key.data;
     }
 
-    const std::vector<unsigned char> ToPKHBytes(const Key& key) const
+    std::vector<unsigned char> ToPKHBytes(const Key& key) const
     {
         if (key.is_hash) return key.data;
         const auto h = Hash160(key.data);
diff --git a/src/test/util/net.h b/src/test/util/net.h
index a52a3ec753d1..fbe8b7d6e00a 100644
--- a/src/test/util/net.h
+++ b/src/test/util/net.h
@@ -133,7 +133,7 @@ constexpr auto ALL_NETWORKS = std::array{
 class StaticContentsSock : public Sock
 {
 public:
-    explicit StaticContentsSock(const std::string& contents) : m_contents{contents}, m_consumed{0}
+    explicit StaticContentsSock(const std::string& contents) : m_contents{contents}
     {
         // Just a dummy number that is not INVALID_SOCKET.
         m_socket = INVALID_SOCKET - 1;
@@ -224,7 +224,7 @@ class StaticContentsSock : public Sock
 
 private:
     const std::string m_contents;
-    mutable size_t m_consumed;
+    mutable size_t m_consumed{0};
 };
 
 std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(int n_candidates, FastRandomContext& random_context);
diff --git a/src/tinyformat.h b/src/tinyformat.h
index 3d128a98929c..d4cf07928679 100644
--- a/src/tinyformat.h
+++ b/src/tinyformat.h
@@ -508,9 +508,6 @@ class FormatArg
 {
     public:
         FormatArg()
-            : m_value(nullptr),
-            m_formatImpl(nullptr),
-            m_toIntImpl(nullptr)
         { }
 
         template<typename T>
@@ -549,10 +546,10 @@ class FormatArg
             return convertToInt<T>::invoke(*static_cast<const T*>(value));
         }
 
-        const void* m_value;
+        const void* m_value{nullptr};
         void (*m_formatImpl)(std::ostream& out, const char* fmtBegin,
-                             const char* fmtEnd, int ntrunc, const void* value);
-        int (*m_toIntImpl)(const void* value);
+                             const char* fmtEnd, int ntrunc, const void* value){nullptr};
+        int (*m_toIntImpl)(const void* value){nullptr};
 };
 
 
diff --git a/src/torcontrol.cpp b/src/torcontrol.cpp
index 8387f467a914..a3110a876ffd 100644
--- a/src/torcontrol.cpp
+++ b/src/torcontrol.cpp
@@ -63,8 +63,8 @@ static const uint16_t DEFAULT_TOR_SOCKS_PORT = 9050;
 
 /****** Low-level TorControlConnection ********/
 
-TorControlConnection::TorControlConnection(struct event_base *_base):
-    base(_base), b_conn(nullptr)
+TorControlConnection::TorControlConnection(struct event_base* _base)
+    : base(_base)
 {
 }
 
diff --git a/src/torcontrol.h b/src/torcontrol.h
index a0603fb1d705..3b4fcb0b7ee3 100644
--- a/src/torcontrol.h
+++ b/src/torcontrol.h
@@ -87,7 +87,7 @@ class TorControlConnection
     /** Libevent event base */
     struct event_base *base;
     /** Connection to control socket */
-    struct bufferevent *b_conn;
+    struct bufferevent* b_conn{nullptr};
     /** Message being received */
     TorControlReply message;
     /** Response handlers */
diff --git a/src/txdb.h b/src/txdb.h
index 493be625128f..886071586514 100644
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -46,7 +46,7 @@ static const int64_t max_filter_index_cache = 1024;
 static const int64_t nMaxCoinsDBCache = 8;
 
 // Actually declared in validation.cpp; can't include because of circular dependency.
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 /** CCoinsView backed by the coin database (chainstate/) */
 class CCoinsViewDB final : public CCoinsView
diff --git a/src/txmempool.h b/src/txmempool.h
index dec456a925c5..959d02b6860f 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -42,7 +42,7 @@
 class CBlockIndex;
 class CChain;
 class CChainState;
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 
 // Forward declaration for CBLSLazyPublicKey:
 template<typename T> class CBLSLazyWrapper;
diff --git a/src/univalue/include/univalue_utffilter.h b/src/univalue/include/univalue_utffilter.h
index f688eaaa30f9..41d8e6bb05f7 100644
--- a/src/univalue/include/univalue_utffilter.h
+++ b/src/univalue/include/univalue_utffilter.h
@@ -13,8 +13,8 @@
 class JSONUTF8StringFilter
 {
 public:
-    explicit JSONUTF8StringFilter(std::string &s):
-        str(s), is_valid(true), codepoint(0), state(0), surpair(0)
+    explicit JSONUTF8StringFilter(std::string& s)
+        : str(s)
     {
     }
     // Write single 8-bit char (may be part of UTF-8 sequence)
@@ -79,10 +79,10 @@ class JSONUTF8StringFilter
     }
 private:
     std::string &str;
-    bool is_valid;
+    bool is_valid{true};
     // Current UTF-8 decoding state
-    unsigned int codepoint;
-    int state; // Top bit to be filled in for next UTF-8 byte, or 0
+    unsigned int codepoint{0};
+    int state{0}; // Top bit to be filled in for next UTF-8 byte, or 0
 
     // Keep track of the following state to handle the following section of
     // RFC4627:
@@ -94,7 +94,7 @@ class JSONUTF8StringFilter
     //    "\uD834\uDD1E".
     //
     //  Two subsequent \u.... may have to be replaced with one actual codepoint.
-    unsigned int surpair; // First half of open UTF-16 surrogate pair, or 0
+    unsigned int surpair{0}; // First half of open UTF-16 surrogate pair, or 0
 
     void append_codepoint(unsigned int codepoint_)
     {
diff --git a/src/util/hasher.cpp b/src/util/hasher.cpp
index 69e2104bd877..92dc25ac4d16 100644
--- a/src/util/hasher.cpp
+++ b/src/util/hasher.cpp
@@ -9,7 +9,7 @@
 
 #include <limits>
 
-SaltedTxidHasher::SaltedTxidHasher() : k0(), k1() {}
+SaltedTxidHasher::SaltedTxidHasher() : k0(GetRand<uint64_t>()), k1(GetRand<uint64_t>()) {}
 
 SaltedOutpointHasher::SaltedOutpointHasher(bool deterministic) :
     k0(deterministic ? 0x8e819f2607a18de6 : GetRand<uint64_t>()),
diff --git a/src/validation.h b/src/validation.h
index 9301ad4c78fd..9a11c25cdb38 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -112,7 +112,7 @@ enum class SynchronizationState {
     POST_INIT
 };
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 extern GlobalMutex g_best_block_mutex;
 extern std::condition_variable g_best_block_cv;
 /** Used to notify getblocktemplate RPC of new tips. */
diff --git a/src/validationinterface.h b/src/validationinterface.h
index 563133d29cc4..80b9a5f22a70 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -12,7 +12,7 @@
 #include <functional>
 #include <memory>
 
-extern RecursiveMutex cs_main;
+extern RecursiveMutex cs_main; // NOLINT(readability-redundant-declaration)
 class BlockValidationState;
 class CBlock;
 class CBlockIndex;
diff --git a/src/wallet/bdb.cpp b/src/wallet/bdb.cpp
index c5c3870fd6fa..38253d60c5d6 100644
--- a/src/wallet/bdb.cpp
+++ b/src/wallet/bdb.cpp
@@ -318,7 +318,7 @@ BerkeleyDatabase::~BerkeleyDatabase()
     }
 }
 
-BerkeleyBatch::BerkeleyBatch(BerkeleyDatabase& database, const bool read_only, bool fFlushOnCloseIn) : pdb(nullptr), activeTxn(nullptr), m_cursor(nullptr), m_database(database)
+BerkeleyBatch::BerkeleyBatch(BerkeleyDatabase& database, const bool read_only, bool fFlushOnCloseIn) : m_database(database)
 {
     database.AddRef();
     database.Open();
diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
index 1d5f21e88d23..436e55736873 100644
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -189,10 +189,10 @@ class BerkeleyBatch : public DatabaseBatch
     bool HasKey(CDataStream&& key) override;
 
 protected:
-    Db* pdb;
+    Db* pdb{nullptr};
     std::string strFile;
-    DbTxn* activeTxn;
-    Dbc* m_cursor;
+    DbTxn* activeTxn{nullptr};
+    Dbc* m_cursor{nullptr};
     bool fReadOnly;
     bool fFlushOnClose;
     BerkeleyEnvironment *env;
diff --git a/src/wallet/bip39_english.h b/src/wallet/bip39_english.h
index 19547f512fa1..aee5cbd39063 100644
--- a/src/wallet/bip39_english.h
+++ b/src/wallet/bip39_english.h
@@ -2073,7 +2073,7 @@ const char * const wordlist[] = {
 "zero",
 "zone",
 "zoo",
-0,
+nullptr,
 };
 
 #endif // BITCOIN_WALLET_BIP39_ENGLISH_H
diff --git a/src/wallet/db.h b/src/wallet/db.h
index fbd0e989c59c..259d09efb45b 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -105,7 +105,7 @@ class WalletDatabase
 {
 public:
     /** Create dummy DB handle */
-    WalletDatabase() : nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0) {}
+    WalletDatabase() : nUpdateCounter(0) {}
     virtual ~WalletDatabase() {};
 
     /** Open the database if it is not already opened. */
@@ -147,9 +147,9 @@ class WalletDatabase
     virtual std::string Format() = 0;
 
     std::atomic<unsigned int> nUpdateCounter;
-    unsigned int nLastSeen;
-    unsigned int nLastFlushed;
-    int64_t nLastWalletUpdate;
+    unsigned int nLastSeen{0};
+    unsigned int nLastFlushed{0};
+    int64_t nLastWalletUpdate{0};
 
     /** Make a DatabaseBatch connected to this database */
     virtual std::unique_ptr<DatabaseBatch> MakeBatch(bool flush_on_close = true) = 0;
diff --git a/src/wallet/hdchain.h b/src/wallet/hdchain.h
index 3a1d21b36200..e2bcc52804e5 100644
--- a/src/wallet/hdchain.h
+++ b/src/wallet/hdchain.h
@@ -9,13 +9,9 @@
 
 namespace wallet {
 /* hd account data model */
-class CHDAccount
-{
-public:
-    uint32_t nExternalChainCounter;
-    uint32_t nInternalChainCounter;
-
-    CHDAccount() : nExternalChainCounter(0), nInternalChainCounter(0) {}
+struct CHDAccount {
+    uint32_t nExternalChainCounter{0};
+    uint32_t nInternalChainCounter{0};
 
     SERIALIZE_METHODS(CHDAccount, obj)
     {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 0ac939954c42..5a3318d73c94 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -268,7 +268,7 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     CKeyingMaterial vMasterKey GUARDED_BY(cs_wallet);
 
     //! if fOnlyMixingAllowed is true, only mixing should be allowed in unlocked wallet
-    bool fOnlyMixingAllowed;
+    bool fOnlyMixingAllowed{false};
 
     bool Unlock(const CKeyingMaterial& vMasterKeyIn, bool fForMixingOnly = false);
 
@@ -461,8 +461,7 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
 
     /** Construct wallet with specified name and database implementation. */
     CWallet(interfaces::Chain* chain, interfaces::CoinJoin::Loader* coinjoin_loader, const std::string& name, const ArgsManager& args, std::unique_ptr<WalletDatabase> database)
-        : fOnlyMixingAllowed(false),
-          m_args(args),
+        : m_args(args),
           m_chain(chain),
           m_coinjoin_loader(coinjoin_loader),
           m_name(name),
@@ -1095,10 +1094,10 @@ class WalletRescanReserver
     using Clock = std::chrono::steady_clock;
     using NowFn = std::function<Clock::time_point()>;
     CWallet& m_wallet;
-    bool m_could_reserve;
+    bool m_could_reserve{false};
     NowFn m_now;
 public:
-    explicit WalletRescanReserver(CWallet& w) : m_wallet(w), m_could_reserve(false) {}
+    explicit WalletRescanReserver(CWallet& w) : m_wallet(w) {}
 
     bool reserve()
     {
diff --git a/src/zmq/zmqabstractnotifier.h b/src/zmq/zmqabstractnotifier.h
index 2f115b93d001..725a98fe8fb3 100644
--- a/src/zmq/zmqabstractnotifier.h
+++ b/src/zmq/zmqabstractnotifier.h
@@ -35,7 +35,7 @@ class CZMQAbstractNotifier
 public:
     static const int DEFAULT_ZMQ_SNDHWM {1000};
 
-    CZMQAbstractNotifier() : psocket(nullptr), outbound_message_high_water_mark(DEFAULT_ZMQ_SNDHWM) { }
+    CZMQAbstractNotifier() : outbound_message_high_water_mark(DEFAULT_ZMQ_SNDHWM) {}
     virtual ~CZMQAbstractNotifier();
 
     template <typename T>
@@ -78,7 +78,7 @@ class CZMQAbstractNotifier
     virtual bool NotifyRecoveredSig(const std::shared_ptr<const llmq::CRecoveredSig>& sig);
 
 protected:
-    void *psocket;
+    void* psocket{nullptr};
     std::string type;
     std::string address;
     int outbound_message_high_water_mark; // aka SNDHWM
diff --git a/src/zmq/zmqnotificationinterface.cpp b/src/zmq/zmqnotificationinterface.cpp
index 423089ed1d94..904e9dca9f27 100644
--- a/src/zmq/zmqnotificationinterface.cpp
+++ b/src/zmq/zmqnotificationinterface.cpp
@@ -22,7 +22,7 @@
 #include <utility>
 #include <vector>
 
-CZMQNotificationInterface::CZMQNotificationInterface() : pcontext(nullptr)
+CZMQNotificationInterface::CZMQNotificationInterface()
 {
 }
 
diff --git a/src/zmq/zmqnotificationinterface.h b/src/zmq/zmqnotificationinterface.h
index 1151941aec51..bfc5b0b4680c 100644
--- a/src/zmq/zmqnotificationinterface.h
+++ b/src/zmq/zmqnotificationinterface.h
@@ -45,7 +45,7 @@ class CZMQNotificationInterface final : public CValidationInterface
 private:
     CZMQNotificationInterface();
 
-    void *pcontext;
+    void* pcontext{nullptr};
     std::list<std::unique_ptr<CZMQAbstractNotifier>> notifiers;
 };