diff --git a/lighter/signer_client.py b/lighter/signer_client.py
index 2734f85..0da893f 100644
--- a/lighter/signer_client.py
+++ b/lighter/signer_client.py
@@ -20,7 +20,6 @@
 from lighter.models.resp_send_tx import RespSendTx
 from lighter.models.resp_send_tx_batch import RespSendTxBatch
 from lighter.transactions import CreateOrder, CancelOrder, Withdraw, CreateGroupedOrders
-from lighter.libc import free
 
 CODE_OK = 200
 
@@ -99,8 +98,10 @@ def decode_and_free(ptr: Any) -> Optional[str]:
             return c_str.decode('utf-8')
         return None
     finally:
-        # Free the memory allocated by the C library
-        free(ptr)
+        # Free the memory using the signer's own Free function to ensure
+        # the same C runtime that allocated the memory also frees it.
+        # This is critical on Windows where different CRTs have separate heaps.
+        __signer.Free(ptr)
 
 
 def __populate_shared_library_functions(signer):
@@ -174,6 +175,9 @@ def __populate_shared_library_functions(signer):
     signer.SignApproveIntegrator.argtypes = [ctypes.c_longlong, ctypes.c_uint32, ctypes.c_uint32, ctypes.c_uint32, ctypes.c_uint32, ctypes.c_longlong, ctypes.c_longlong, ctypes.c_int, ctypes.c_longlong]
     signer.SignApproveIntegrator.restype = SignedTxResponse
 
+    signer.Free.argtypes = [ctypes.c_void_p]
+    signer.Free.restype = None
+
 
 def get_signer():
     # check if singleton exists already
diff --git a/lighter/signers/lighter-signer-darwin-arm64.dylib b/lighter/signers/lighter-signer-darwin-arm64.dylib
index 822bbfb..58f2023 100644
Binary files a/lighter/signers/lighter-signer-darwin-arm64.dylib and b/lighter/signers/lighter-signer-darwin-arm64.dylib differ
diff --git a/lighter/signers/lighter-signer-darwin-arm64.h b/lighter/signers/lighter-signer-darwin-arm64.h
index 1772296..edd9ecd 100644
--- a/lighter/signers/lighter-signer-darwin-arm64.h
+++ b/lighter/signers/lighter-signer-darwin-arm64.h
@@ -144,6 +144,7 @@ extern SignedTxResponse SignUpdateMargin(int cMarketIndex, long long cUSDCAmount
 extern SignedTxResponse SignStakeAssets(long long cStakingPoolIndex, long long cShareAmount, long long cNonce, int cApiKeyIndex, long long cAccountIndex);
 extern SignedTxResponse SignUnstakeAssets(long long cStakingPoolIndex, long long cShareAmount, long long cNonce, int cApiKeyIndex, long long cAccountIndex);
 extern SignedTxResponse SignApproveIntegrator(long long cIntegratorIndex, uint32_t cMaxPerpsTakerFee, uint32_t cMaxPerpsMakerFee, uint32_t cMaxSpotTakerFee, uint32_t cMaxSpotMakerFee, long long cApprovalExpiry, long long cNonce, int cApiKeyIndex, long long cAccountIndex);
+extern void Free(void* ptr);
 
 #ifdef __cplusplus
 }
diff --git a/lighter/signers/lighter-signer-linux-amd64.h b/lighter/signers/lighter-signer-linux-amd64.h
index 37b97d6..d14c8d4 100644
--- a/lighter/signers/lighter-signer-linux-amd64.h
+++ b/lighter/signers/lighter-signer-linux-amd64.h
@@ -136,6 +136,7 @@ extern SignedTxResponse SignUpdateMargin(int cMarketIndex, long long int cUSDCAm
 extern SignedTxResponse SignStakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern SignedTxResponse SignUnstakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern SignedTxResponse SignApproveIntegrator(long long int cIntegratorIndex, uint32_t cMaxPerpsTakerFee, uint32_t cMaxPerpsMakerFee, uint32_t cMaxSpotTakerFee, uint32_t cMaxSpotMakerFee, long long int cApprovalExpiry, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
+extern void Free(void* ptr);
 
 #ifdef __cplusplus
 }
diff --git a/lighter/signers/lighter-signer-linux-amd64.so b/lighter/signers/lighter-signer-linux-amd64.so
index da328c2..bcbe58d 100644
Binary files a/lighter/signers/lighter-signer-linux-amd64.so and b/lighter/signers/lighter-signer-linux-amd64.so differ
diff --git a/lighter/signers/lighter-signer-linux-arm64.h b/lighter/signers/lighter-signer-linux-arm64.h
index 37b97d6..d14c8d4 100644
--- a/lighter/signers/lighter-signer-linux-arm64.h
+++ b/lighter/signers/lighter-signer-linux-arm64.h
@@ -136,6 +136,7 @@ extern SignedTxResponse SignUpdateMargin(int cMarketIndex, long long int cUSDCAm
 extern SignedTxResponse SignStakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern SignedTxResponse SignUnstakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern SignedTxResponse SignApproveIntegrator(long long int cIntegratorIndex, uint32_t cMaxPerpsTakerFee, uint32_t cMaxPerpsMakerFee, uint32_t cMaxSpotTakerFee, uint32_t cMaxSpotMakerFee, long long int cApprovalExpiry, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
+extern void Free(void* ptr);
 
 #ifdef __cplusplus
 }
diff --git a/lighter/signers/lighter-signer-linux-arm64.so b/lighter/signers/lighter-signer-linux-arm64.so
index d336bb2..6b68e88 100644
Binary files a/lighter/signers/lighter-signer-linux-arm64.so and b/lighter/signers/lighter-signer-linux-arm64.so differ
diff --git a/lighter/signers/lighter-signer-windows-amd64.dll b/lighter/signers/lighter-signer-windows-amd64.dll
index 1cba0ae..dd5aeaa 100644
Binary files a/lighter/signers/lighter-signer-windows-amd64.dll and b/lighter/signers/lighter-signer-windows-amd64.dll differ
diff --git a/lighter/signers/lighter-signer-windows-amd64.h b/lighter/signers/lighter-signer-windows-amd64.h
index 9537538..b02057a 100644
--- a/lighter/signers/lighter-signer-windows-amd64.h
+++ b/lighter/signers/lighter-signer-windows-amd64.h
@@ -136,6 +136,7 @@ extern __declspec(dllexport) SignedTxResponse SignUpdateMargin(int cMarketIndex,
 extern __declspec(dllexport) SignedTxResponse SignStakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern __declspec(dllexport) SignedTxResponse SignUnstakeAssets(long long int cStakingPoolIndex, long long int cShareAmount, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
 extern __declspec(dllexport) SignedTxResponse SignApproveIntegrator(long long int cIntegratorIndex, uint32_t cMaxPerpsTakerFee, uint32_t cMaxPerpsMakerFee, uint32_t cMaxSpotTakerFee, uint32_t cMaxSpotMakerFee, long long int cApprovalExpiry, long long int cNonce, int cApiKeyIndex, long long int cAccountIndex);
+extern __declspec(dllexport) void Free(void* ptr);
 
 #ifdef __cplusplus
 }