diff --git a/handlers.client.ts b/handlers.client.ts
index b7ff619..968d37d 100644
--- a/handlers.client.ts
+++ b/handlers.client.ts
@@ -187,7 +187,12 @@ async function handleWebSocket(
   message: RequestStartMessage,
   state: ClientState,
 ) {
-  const ws = new WebSocket(new URL(message.url, state.localAddr));
+  const target = new URL(message.url, state.localAddr);
+  // Coerce http(s): -> ws(s): so spec-strict runtimes (e.g. Bun) accept it.
+  // Node's undici silently rewrites the scheme, but Bun keeps `http:` and
+  // the handshake fails immediately, breaking HMR (Vite/Next) through the tunnel.
+  target.protocol = target.protocol === "https:" ? "wss:" : "ws:";
+  const ws = new WebSocket(target);
   try {
     const wsCh = await makeWebSocket<ArrayBuffer, ArrayBuffer, ArrayBuffer>(
       ws,
diff --git a/package-lock.json b/package-lock.json
index e24e47c..b4778c5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@deco-cx/warp-node",
-  "version": "0.3.9",
+  "version": "0.3.21-debug.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@deco-cx/warp-node",
-      "version": "0.3.9",
+      "version": "0.3.21-debug.2",
       "license": "MIT",
       "dependencies": {
         "undici": "^6.21.0",
@@ -22,7 +22,7 @@
         "wrangler": "^3.91.0"
       },
       "engines": {
-        "node": ">=20.0.0"
+        "node": ">=22.0.0"
       }
     },
     "node_modules/@cloudflare/kv-asset-handler": {