diff --git a/src/cli.rs b/src/cli.rs
index 9aa92e4..3c1d4b1 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -44,6 +44,9 @@ pub struct Opt {
     #[clap(long, display_order = 10)]
     /// Output logs in alternative format (same as kaspad)
     pub altlogs: bool,
+    #[clap(long = "user-agent-suffix", display_order = 11)]
+    /// Custom user agent suffix (max 20 characters)
+    pub user_agent_suffix: Option<String>,
 }
 
 fn parse_devfund_percent(s: &str) -> Result<u16, &'static str> {
@@ -82,6 +85,15 @@ impl Opt {
         }
         log::info!("Kaspad address: {}", self.kaspad_address);
 
+        if let Some(suffix) = &self.user_agent_suffix {
+            if suffix.contains('/') {
+                return Err("--user-agent-suffix cannot contain '/' characters".into());
+            }
+            if suffix.chars().count() > 20 {
+                return Err("--user-agent-suffix must be at most 20 characters".into());
+            }
+        }
+
         Ok(())
     }
 
diff --git a/src/client.rs b/src/client.rs
index f0ff633..695aec9 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -23,20 +23,39 @@ pub struct KaspadHandler {
     devfund_address: Option<String>,
     devfund_percent: u16,
     block_template_ctr: u64,
+    extra_data: String,
 }
 
 impl KaspadHandler {
-    pub async fn connect<D>(address: D, miner_address: String, mine_when_not_synced: bool) -> Result<Self, Error>
+    pub async fn connect<D>(
+        address: D,
+        miner_address: String,
+        mine_when_not_synced: bool,
+        user_agent_suffix: Option<String>,
+    ) -> Result<Self, Error>
     where
         D: TryInto<tonic::transport::Endpoint>,
         D::Error: Into<Error>,
     {
         let mut client = RpcClient::connect(address).await?;
         let (send_channel, recv) = mpsc::channel(3);
+
+        let extra_data = match user_agent_suffix {
+            Some(suffix) => {
+                let extra_data = format!("{}/{}", EXTRA_DATA, suffix);
+                info!("Using user agent: {}", extra_data);
+                extra_data
+            }
+            None => {
+                info!("Using user agent: {}, specify --user-agent-suffix to customize", EXTRA_DATA);
+                EXTRA_DATA.to_string()
+            }
+        };
+
         send_channel.send(GetInfoRequestMessage {}.into()).await?;
         send_channel
             .send(
-                GetBlockTemplateRequestMessage { pay_address: miner_address.clone(), extra_data: EXTRA_DATA.into() }
+                GetBlockTemplateRequestMessage { pay_address: miner_address.clone(), extra_data: extra_data.clone() }
                     .into(),
             )
             .await?;
@@ -50,6 +69,7 @@ impl KaspadHandler {
             devfund_address: None,
             devfund_percent: 0,
             block_template_ctr: 0,
+            extra_data,
         })
     }
 
@@ -70,7 +90,7 @@ impl KaspadHandler {
             _ => self.miner_address.clone(),
         };
         self.block_template_ctr += 1;
-        self.client_send(GetBlockTemplateRequestMessage { pay_address, extra_data: EXTRA_DATA.into() }).await
+        self.client_send(GetBlockTemplateRequestMessage { pay_address, extra_data: self.extra_data.clone() }).await
     }
 
     pub async fn listen(&mut self, miner: &mut MinerManager, shutdown: ShutdownHandler) -> Result<(), Error> {
diff --git a/src/main.rs b/src/main.rs
index c99ec46..dca2a3c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -77,9 +77,13 @@ async fn main() -> Result<(), Error> {
     let _shutdown_when_dropped = shutdown.arm();
 
     while !shutdown.is_shutdown() {
-        let mut client =
-            KaspadHandler::connect(opt.kaspad_address.clone(), opt.mining_address.clone(), opt.mine_when_not_synced)
-                .await?;
+        let mut client = KaspadHandler::connect(
+            opt.kaspad_address.clone(),
+            opt.mining_address.clone(),
+            opt.mine_when_not_synced,
+            opt.user_agent_suffix.clone(),
+        )
+        .await?;
         if let Some(devfund_address) = &opt.devfund_address {
             client.add_devfund(devfund_address.clone(), opt.devfund_percent);
             info!(