diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63412d2..96b5f25 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,10 @@ The minor version will be incremented upon a breaking change and the patch versi
 
 - richat-v10.0.0
 
+### Fixes
+
+- richat: fix unknown unsubscribe id handler in pubsub ([#209](https://github.com/lamports-dev/richat/pull/209))
+
 ### Breaking
 
 - richat: remove entries from subscribe_accounts subscription ([#210](https://github.com/lamports-dev/richat/pull/210))
diff --git a/richat/src/pubsub/server.rs b/richat/src/pubsub/server.rs
index eb9404f..52279d0 100644
--- a/richat/src/pubsub/server.rs
+++ b/richat/src/pubsub/server.rs
@@ -24,7 +24,9 @@ use {
         rt::tokio::{TokioExecutor, TokioIo},
         server::conn::auto::Builder as ServerBuilder,
     },
-    jsonrpsee_types::{Extensions, ResponsePayload, TwoPointZero},
+    jsonrpsee_types::{
+        ErrorCode, ErrorObject, ErrorObjectOwned, Extensions, ResponsePayload, TwoPointZero,
+    },
     richat_shared::jsonrpc::helpers::get_x_subscription_id,
     solana_nohash_hasher::IntMap,
     solana_rpc_client_api::response::RpcVersionInfo,
@@ -304,16 +306,16 @@ impl PubSubServer {
                             let _ = tx.send(());
                         },
                         Ok(WriteRequest::Message { message, tx }) => {
-                            let result = match message.config {
+                            let result: Result<serde_json::Value, ErrorObjectOwned> = match message.config {
                                 SubscribeConfig::GetVersion => {
                                     let version = solana_version::Version::default();
-                                    serde_json::to_value(&RpcVersionInfo {
+                                    Ok(serde_json::to_value(&RpcVersionInfo {
                                         solana_core: version.to_string(),
                                         feature_set: Some(version.feature_set),
                                     })
-                                    .expect("json serialization never fail")
+                                    .expect("json serialization never fail"))
                                 },
-                                SubscribeConfig::GetVersionRichat => VERSION.create_grpc_version_info().value(),
+                                SubscribeConfig::GetVersionRichat => Ok(VERSION.create_grpc_version_info().value()),
                                 SubscribeConfig::Unsubscribe { id } => {
                                     let (tx, rx) = oneshot::channel();
                                     if clients_tx.send(ClientRequest::Unsubscribe {
@@ -333,8 +335,14 @@ impl PubSubServer {
                                             )
                                             .decrement(1);
                                         }
+                                        Ok(true.into())
+                                    } else {
+                                        Err(ErrorObject::owned::<()>(
+                                            ErrorCode::InvalidParams.code(),
+                                            "Invalid subscription id.",
+                                            None,
+                                        ))
                                     }
-                                    removed.into()
                                 },
                                 config => {
                                     let (tx, rx) = oneshot::channel();
@@ -353,13 +361,17 @@ impl PubSubServer {
                                         "method" => method.as_str()
                                     )
                                     .increment(1);
-                                    id.into()
+                                    Ok(id.into())
                                 },
                             };
 
+                            let payload = match result {
+                                Ok(value) => ResponsePayload::success(value),
+                                Err(error) => ResponsePayload::error(error),
+                            };
                             let vec = serde_json::to_vec(&jsonrpsee_types::Response {
                                 jsonrpc: Some(TwoPointZero),
-                                payload: ResponsePayload::success(result),
+                                payload,
                                 id: message.id,
                                 extensions: Extensions::default(), // doesn't matter, as it is not used in serialize
                             }).expect("json serialization never fail");
@@ -464,3 +476,41 @@ fn create_frame_close(frame: Frame) -> Result<Frame, WebSocketError> {
 
     Ok(Frame::close_raw(frame.payload.to_owned().into()))
 }
+
+#[cfg(test)]
+mod tests {
+    use {
+        super::*,
+        jsonrpsee_types::Id,
+        serde_json::{Value, json},
+    };
+
+    // Agave returns this exact error for unsubscribe with an unknown id.
+    #[test]
+    fn unsubscribe_invalid_id_wire_format_matches_agave() {
+        let error = ErrorObject::owned::<()>(
+            ErrorCode::InvalidParams.code(),
+            "Invalid subscription id.",
+            None,
+        );
+        let vec = serde_json::to_vec(&jsonrpsee_types::Response {
+            jsonrpc: Some(TwoPointZero),
+            payload: ResponsePayload::<Value>::error(error),
+            id: Id::Number(42),
+            extensions: Extensions::default(),
+        })
+        .unwrap();
+        let parsed: Value = serde_json::from_slice(&vec).unwrap();
+        assert_eq!(
+            parsed,
+            json!({
+                "jsonrpc": "2.0",
+                "error": {
+                    "code": -32602,
+                    "message": "Invalid subscription id.",
+                },
+                "id": 42,
+            })
+        );
+    }
+}