diff --git a/src/clients/mod.rs b/src/clients/mod.rs
index b9707f9..3d14737 100644
--- a/src/clients/mod.rs
+++ b/src/clients/mod.rs
@@ -1,8 +1,9 @@
 pub mod supervisor_client;
 pub mod mycelium_client;
+pub mod types;
 
+pub use types::Destination;
 pub use supervisor_client::{
-    Destination,
     SupervisorClient,
     SupervisorClientError,
 };
diff --git a/src/clients/mycelium_client.rs b/src/clients/mycelium_client.rs
index 58557dc..f4567cf 100644
--- a/src/clients/mycelium_client.rs
+++ b/src/clients/mycelium_client.rs
@@ -2,16 +2,17 @@ use std::sync::Arc;
 use std::sync::atomic::{AtomicU64, Ordering};
 
 use reqwest::Client as HttpClient;
-use serde::Deserialize;
+
 use serde_json::{Value, json};
 use thiserror::Error;
 
 use crate::models::TransportStatus;
+use crate::clients::Destination;
 
-/// Lightweight client for querying Mycelium transport status
+/// Lightweight client for Mycelium JSON-RPC (send + query status)
 #[derive(Clone)]
 pub struct MyceliumClient {
-    base_url: String,       // e.g. http://127.0.0.1:9651
+    base_url: String,       // e.g. http://127.0.0.1:8990
     http: HttpClient,
     id_counter: Arc<AtomicU64>,
 }
@@ -22,6 +23,8 @@ pub enum MyceliumClientError {
     Http(#[from] reqwest::Error),
     #[error("JSON error: {0}")]
     Json(#[from] serde_json::Error),
+    #[error("Transport timed out waiting for a reply (408)")]
+    TransportTimeout,
     #[error("JSON-RPC error: {0}")]
     RpcError(String),
     #[error("Invalid response: {0}")]
@@ -56,6 +59,9 @@ impl MyceliumClient {
         if let Some(err) = body.get("error") {
             let code = err.get("code").and_then(|v| v.as_i64()).unwrap_or(0);
             let msg = err.get("message").and_then(|v| v.as_str()).unwrap_or("unknown error");
+            if code == 408 {
+                return Err(MyceliumClientError::TransportTimeout);
+            }
             return Err(MyceliumClientError::RpcError(format!("code={code} msg={msg}")));
         }
         if !status.is_success() {
@@ -94,4 +100,109 @@ impl MyceliumClient {
             _ => None,
         }
     }
+
+    /// Build params object for pushMessage without performing any network call.
+    /// Exposed for serializer-only tests and reuse.
+    pub(crate) fn build_push_params(
+        dst: &Destination,
+        topic: &str,
+        payload_b64: &str,
+        reply_timeout: Option<u64>,
+    ) -> Value {
+        let dst_v = match dst {
+            Destination::Ip(ip) => json!({ "ip": ip.to_string() }),
+            Destination::Pk(pk) => json!({ "pk": pk }),
+        };
+        let message = json!({
+            "dst": dst_v,
+            "topic": topic,
+            "payload": payload_b64,
+        });
+        let mut params = json!({ "message": message });
+        if let Some(rt) = reply_timeout {
+            params["reply_timeout"] = json!(rt);
+        }
+        params
+    }
+
+    /// pushMessage: send a message with dst/topic/payload. Optional reply_timeout for sync replies.
+    pub async fn push_message(
+        &self,
+        dst: &Destination,
+        topic: &str,
+        payload_b64: &str,
+        reply_timeout: Option<u64>,
+    ) -> Result<Value, MyceliumClientError> {
+        let params = Self::build_push_params(dst, topic, payload_b64, reply_timeout);
+        let body = self.jsonrpc("pushMessage", params).await?;
+        let result = body.get("result").ok_or_else(|| {
+            MyceliumClientError::InvalidResponse(format!("missing result in response: {body}"))
+        })?;
+        Ok(result.clone())
+    }
+
+    /// Helper to extract outbound message id from pushMessage result (InboundMessage or PushMessageResponseId)
+    pub fn extract_message_id_from_result(result: &Value) -> Option<String> {
+        result.get("id").and_then(|v| v.as_str()).map(|s| s.to_string())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::clients::Destination;
+
+    #[test]
+    fn build_push_params_shapes_ip_pk_and_timeout() {
+        // IP destination
+        let p1 = MyceliumClient::build_push_params(
+            &Destination::Ip("2001:db8::1".parse().unwrap()),
+            "supervisor.rpc",
+            "Zm9vYmFy", // "foobar"
+            Some(10),
+        );
+        let msg1 = p1.get("message").unwrap();
+        assert_eq!(msg1.get("topic").unwrap().as_str().unwrap(), "supervisor.rpc");
+        assert_eq!(msg1.get("payload").unwrap().as_str().unwrap(), "Zm9vYmFy");
+        assert_eq!(
+            msg1.get("dst").unwrap().get("ip").unwrap().as_str().unwrap(),
+            "2001:db8::1"
+        );
+        assert_eq!(p1.get("reply_timeout").unwrap().as_u64().unwrap(), 10);
+
+        // PK destination without timeout
+        let p2 = MyceliumClient::build_push_params(
+            &Destination::Pk("bb39b4a3a4efd70f3e05e37887677e02efbda14681d0acd3882bc0f754792c32".into()),
+            "supervisor.rpc",
+            "YmF6", // "baz"
+            None,
+        );
+        let msg2 = p2.get("message").unwrap();
+        assert_eq!(
+            msg2.get("dst").unwrap().get("pk").unwrap().as_str().unwrap(),
+            "bb39b4a3a4efd70f3e05e37887677e02efbda14681d0acd3882bc0f754792c32"
+        );
+        assert!(p2.get("reply_timeout").is_none());
+    }
+
+    #[test]
+    fn extract_message_id_variants() {
+        // PushMessageResponseId
+        let r1 = json!({"id":"0123456789abcdef"});
+        assert_eq!(
+            MyceliumClient::extract_message_id_from_result(&r1).unwrap(),
+            "0123456789abcdef"
+        );
+
+        // InboundMessage-like
+        let r2 = json!({
+            "id":"fedcba9876543210",
+            "srcIp":"449:abcd:0123:defa::1",
+            "payload":"hpV+"
+        });
+        assert_eq!(
+            MyceliumClient::extract_message_id_from_result(&r2).unwrap(),
+            "fedcba9876543210"
+        );
+    }
 }
\ No newline at end of file
diff --git a/src/clients/supervisor_client.rs b/src/clients/supervisor_client.rs
index 4cc4049..80b07d8 100644
--- a/src/clients/supervisor_client.rs
+++ b/src/clients/supervisor_client.rs
@@ -1,28 +1,20 @@
-use std::net::IpAddr;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicU64, Ordering};
 
 use base64::Engine;
 use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
-use reqwest::Client as HttpClient;
 use serde_json::{Value, json};
 use thiserror::Error;
 
-/// Destination for Mycelium messages
-#[derive(Clone, Debug)]
-pub enum Destination {
-    Ip(IpAddr),
-    Pk(String), // 64-hex public key
-}
+use crate::clients::{Destination, MyceliumClient, MyceliumClientError};
 
 #[derive(Clone)]
 pub struct SupervisorClient {
-    base_url: String,         // e.g. "http://127.0.0.1:8990"
-    destination: Destination, // ip or pk
-    topic: String,            // e.g. "supervisor.rpc"
-    secret: Option<String>,   // optional, required by several supervisor methods
-    http: HttpClient,
-    id_counter: Arc<AtomicU64>, // JSON-RPC id generator (for inner + outer requests)
+    mycelium: Arc<MyceliumClient>, // Delegated Mycelium transport
+    destination: Destination,      // ip or pk
+    topic: String,                 // e.g. "supervisor.rpc"
+    secret: Option<String>,        // optional, required by several supervisor methods
+    id_counter: Arc<AtomicU64>,    // JSON-RPC id generator (for inner supervisor requests)
 }
 
 #[derive(Debug, Error)]
@@ -41,8 +33,37 @@ pub enum SupervisorClientError {
     MissingSecret,
 }
 
+impl From<MyceliumClientError> for SupervisorClientError {
+    fn from(e: MyceliumClientError) -> Self {
+        match e {
+            MyceliumClientError::TransportTimeout => SupervisorClientError::TransportTimeout,
+            MyceliumClientError::RpcError(m) => SupervisorClientError::RpcError(m),
+            MyceliumClientError::InvalidResponse(m) => SupervisorClientError::InvalidResponse(m),
+            MyceliumClientError::Http(err) => SupervisorClientError::Http(err),
+            MyceliumClientError::Json(err) => SupervisorClientError::Json(err),
+        }
+    }
+}
+
 impl SupervisorClient {
-    /// Create a new client. base_url defaults to Mycelium spec "http://127.0.0.1:8990" if empty.
+    /// Preferred constructor: provide a shared Mycelium client.
+    pub fn new_with_client(
+        mycelium: Arc<MyceliumClient>,
+        destination: Destination,
+        topic: impl Into<String>,
+        secret: Option<String>,
+    ) -> Self {
+        Self {
+            mycelium,
+            destination,
+            topic: topic.into(),
+            secret,
+            id_counter: Arc::new(AtomicU64::new(1)),
+        }
+    }
+
+    /// Backward-compatible constructor that builds a Mycelium client from base_url.
+    /// base_url defaults to Mycelium spec "http://127.0.0.1:8990" if empty.
     pub fn new(
         base_url: impl Into<String>,
         destination: Destination,
@@ -53,21 +74,15 @@ impl SupervisorClient {
         if url.is_empty() {
             url = "http://127.0.0.1:8990".to_string();
         }
-        let http = HttpClient::builder().build()?;
-        Ok(Self {
-            base_url: url,
-            destination,
-            topic: topic.into(),
-            secret,
-            http,
-            id_counter: Arc::new(AtomicU64::new(1)),
-        })
+        let mycelium = Arc::new(MyceliumClient::new(url)?);
+        Ok(Self::new_with_client(mycelium, destination, topic, secret))
     }
 
     fn next_id(&self) -> u64 {
         self.id_counter.fetch_add(1, Ordering::Relaxed)
     }
 
+    /// Internal helper used by tests to inspect dst JSON shape.
     fn build_dst(&self) -> Value {
         match &self.destination {
             Destination::Ip(ip) => json!({ "ip": ip.to_string() }),
@@ -89,49 +104,6 @@ impl SupervisorClient {
         Ok(BASE64_STANDARD.encode(s.as_bytes()))
     }
 
-    fn build_push_request(&self, payload_b64: String) -> Value {
-        let dst = self.build_dst();
-        let msg = json!({
-            "dst": dst,
-            "topic": self.topic,
-            "payload": payload_b64
-        });
-
-        // Async path: no reply_timeout attached
-        json!({
-            "jsonrpc": "2.0",
-            "id": self.next_id(),
-            "method": "pushMessage",
-            "params": [ { "message": msg } ]
-        })
-    }
-
-    async fn send_push(&self, req: &Value) -> Result<Value, SupervisorClientError> {
-        let resp = self.http.post(&self.base_url).json(req).send().await?;
-        let status = resp.status();
-        let body: Value = resp.json().await?;
-        // JSON-RPC error object handling
-        if let Some(err) = body.get("error") {
-            let code = err.get("code").and_then(|v| v.as_i64()).unwrap_or(0);
-            let msg = err
-                .get("message")
-                .and_then(|v| v.as_str())
-                .unwrap_or("unknown error");
-            if code == 408 {
-                return Err(SupervisorClientError::TransportTimeout);
-            }
-            return Err(SupervisorClientError::RpcError(format!(
-                "code={code} msg={msg}"
-            )));
-        }
-        if !status.is_success() {
-            return Err(SupervisorClientError::RpcError(format!(
-                "HTTP status {status}, body {body}"
-            )));
-        }
-        Ok(body)
-    }
-
     fn extract_message_id_from_result(result: &Value) -> Option<String> {
         // Two possibilities per Mycelium spec oneOf:
         // - PushMessageResponseId: { "id": "0123456789abcdef" }
@@ -142,34 +114,28 @@ impl SupervisorClient {
             .map(|s| s.to_string())
     }
 
-    /// Generic call: build supervisor JSON-RPC message, wrap in Mycelium pushMessage, return outbound message id (hex).
+    /// Generic call: build supervisor JSON-RPC message, send via Mycelium pushMessage, return outbound message id (hex).
     pub async fn call(&self, method: &str, params: Value) -> Result<String, SupervisorClientError> {
         let inner = self.build_supervisor_payload(method, params);
         let payload_b64 = Self::encode_payload(&inner)?;
-        let push_req = self.build_push_request(payload_b64);
-        let resp = self.send_push(&push_req).await?;
+        let result = self
+            .mycelium
+            .push_message(&self.destination, &self.topic, &payload_b64, None)
+            .await?;
 
-        // Expect "result" to be either inbound message or response id
-        match resp.get("result") {
-            Some(res_obj) => {
-                if let Some(id) = Self::extract_message_id_from_result(res_obj) {
-                    return Ok(id);
-                }
-                // Some servers might return the oneOf wrapped, handle len==1 array defensively (not in spec but resilient)
-                if let Some(arr) = res_obj.as_array()
-                    && arr.len() == 1
-                    && let Some(id) = Self::extract_message_id_from_result(&arr[0])
-                {
-                    return Ok(id);
-                }
-                Err(SupervisorClientError::InvalidResponse(format!(
-                    "result did not contain message id: {res_obj}"
-                )))
-            }
-            None => Err(SupervisorClientError::InvalidResponse(format!(
-                "missing result in response: {resp}"
-            ))),
+        if let Some(id) = MyceliumClient::extract_message_id_from_result(&result) {
+            return Ok(id);
         }
+        // Some servers might return the oneOf wrapped, handle len==1 array defensively (not in spec but resilient)
+        if let Some(arr) = result.as_array()
+            && arr.len() == 1
+            && let Some(id) = MyceliumClient::extract_message_id_from_result(&arr[0])
+        {
+            return Ok(id);
+        }
+        Err(SupervisorClientError::InvalidResponse(format!(
+            "result did not contain message id: {result}"
+        )))
     }
 
     fn need_secret(&self) -> Result<&str, SupervisorClientError> {
@@ -334,8 +300,10 @@ impl SupervisorClient {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::net::IpAddr;
 
     fn mk_client() -> SupervisorClient {
+        // Uses the legacy constructor but will not issue real network calls in these tests.
         SupervisorClient::new(
             "http://127.0.0.1:8990",
             Destination::Pk(
@@ -368,20 +336,21 @@ mod tests {
     }
 
     #[test]
-    fn wraps_supervisor_payload_in_push_message() {
+    fn encodes_supervisor_payload_b64() {
         let c = mk_client();
         let payload = c.build_supervisor_payload("list_runners", json!([]));
         let b64 = SupervisorClient::encode_payload(&payload).unwrap();
-        let req = c.build_push_request(b64);
-        assert_eq!(req.get("method").unwrap().as_str().unwrap(), "pushMessage");
-        let params = req.get("params").unwrap().as_array().unwrap();
-        let msg = params[0].get("message").unwrap();
-        assert!(msg.get("payload").is_some());
+
+        // decode and compare round-trip JSON
+        let raw = base64::engine::general_purpose::STANDARD
+            .decode(b64.as_bytes())
+            .unwrap();
+        let decoded: Value = serde_json::from_slice(&raw).unwrap();
         assert_eq!(
-            msg.get("topic").unwrap().as_str().unwrap(),
-            "supervisor.rpc"
+            decoded.get("method").unwrap().as_str().unwrap(),
+            "list_runners"
         );
-        assert!(msg.get("dst").unwrap().get("pk").is_some());
+        assert_eq!(decoded.get("jsonrpc").unwrap().as_str().unwrap(), "2.0");
     }
 
     #[test]
diff --git a/src/clients/types.rs b/src/clients/types.rs
new file mode 100644
index 0000000..b21533b
--- /dev/null
+++ b/src/clients/types.rs
@@ -0,0 +1,9 @@
+use std::net::IpAddr;
+
+/// Destination for Mycelium messages (shared by clients)
+#[derive(Clone, Debug)]
+pub enum Destination {
+    Ip(IpAddr),
+    /// 64-hex public key of the receiver node
+    Pk(String),
+}
\ No newline at end of file
diff --git a/src/router.rs b/src/router.rs
index 908b0ff..3177c47 100644
--- a/src/router.rs
+++ b/src/router.rs
@@ -34,6 +34,18 @@ pub fn start_router(service: AppService, cfg: RouterConfig) -> Vec<tokio::task::
         let cfg_cloned = cfg.clone();
         let handle = tokio::spawn(async move {
             let sem = Arc::new(Semaphore::new(cfg_cloned.concurrency));
+
+            // Create a shared Mycelium client for this context loop (retry until available)
+            let mycelium = loop {
+                match MyceliumClient::new(cfg_cloned.base_url.clone()) {
+                    Ok(c) => break Arc::new(c),
+                    Err(e) => {
+                        eprintln!("[router ctx={}] MyceliumClient init error: {}", ctx_id, e);
+                        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                    }
+                }
+            };
+
             loop {
                 // Pop next message key (blocking with timeout)
                 match service_cloned.brpop_msg_out(ctx_id, 1).await {
@@ -52,16 +64,19 @@ pub fn start_router(service: AppService, cfg: RouterConfig) -> Vec<tokio::task::
                         };
                         let service_task = service_cloned.clone();
                         let cfg_task = cfg_cloned.clone();
-                        tokio::spawn(async move {
-                            // Ensure permit is dropped at end of task
-                            let _permit = permit;
-                            if let Err(e) =
-                                deliver_one(&service_task, &cfg_task, ctx_id, &key).await
-                            {
-                                eprintln!(
-                                    "[router ctx={}] delivery error for {}: {}",
-                                    ctx_id, key, e
-                                );
+                        tokio::spawn({
+                            let mycelium = mycelium.clone();
+                            async move {
+                                // Ensure permit is dropped at end of task
+                                let _permit = permit;
+                                if let Err(e) =
+                                    deliver_one(&service_task, &cfg_task, ctx_id, &key, mycelium).await
+                                {
+                                    eprintln!(
+                                        "[router ctx={}] delivery error for {}: {}",
+                                        ctx_id, key, e
+                                    );
+                                }
                             }
                         });
                     }
@@ -87,6 +102,7 @@ async fn deliver_one(
     cfg: &RouterConfig,
     context_id: u32,
     msg_key: &str,
+    mycelium: Arc<MyceliumClient>,
 ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     // Parse "message:{caller_id}:{id}"
     let (caller_id, id) = parse_message_key(msg_key)
@@ -120,12 +136,12 @@ async fn deliver_one(
     } else {
         Destination::Ip(runner.address)
     };
-    let client = SupervisorClient::new(
-        cfg.base_url.clone(),
+    let client = SupervisorClient::new_with_client(
+        mycelium.clone(),
         dest,
         cfg.topic.clone(),
         None, // secret
-    )?;
+    );
 
     // Build supervisor method and params from Message
     let method = msg.message.clone();
@@ -153,27 +169,14 @@ async fn deliver_one(
     // Spawn transport-status poller
     {
         let service_poll = service.clone();
-        let base_url = cfg.base_url.clone();
         let poll_interval = std::time::Duration::from_secs(cfg.transport_poll_interval_secs);
         let poll_timeout = std::time::Duration::from_secs(cfg.transport_poll_timeout_secs);
         let out_id_cloned = out_id.clone();
+        let mycelium = mycelium.clone();
 
         tokio::spawn(async move {
             let start = std::time::Instant::now();
-            let client = match MyceliumClient::new(base_url) {
-                Ok(c) => c,
-                Err(e) => {
-                    let _ = service_poll
-                        .append_message_logs(
-                            context_id,
-                            caller_id,
-                            id,
-                            vec![format!("MyceliumClient init error: {e}")],
-                        )
-                        .await;
-                    return;
-                }
-            };
+            let client = mycelium;
 
             let mut last_status: Option<TransportStatus> = Some(TransportStatus::Sent);