diff --git a/backend/api_server.py b/backend/api_server.py
index 23a5867..fa5c583 100644
--- a/backend/api_server.py
+++ b/backend/api_server.py
@@ -151,14 +151,24 @@ class APIServer:
 
         @app.post("/api/start")
         async def start_transcription():
-            success, message = ctrl.start_transcription()
+            import asyncio
+            # Run in thread pool to avoid blocking the event loop
+            # (start_recording can block up to 15s waiting for Deepgram WS)
+            loop = asyncio.get_event_loop()
+            success, message = await loop.run_in_executor(
+                None, ctrl.start_transcription
+            )
             if not success:
                 raise HTTPException(status_code=400, detail=message)
             return {"status": "ok", "message": message}
 
         @app.post("/api/stop")
         async def stop_transcription():
-            success, message = ctrl.stop_transcription()
+            import asyncio
+            loop = asyncio.get_event_loop()
+            success, message = await loop.run_in_executor(
+                None, ctrl.stop_transcription
+            )
             if not success:
                 raise HTTPException(status_code=400, detail=message)
             return {"status": "ok", "message": message}
@@ -223,7 +233,11 @@ class APIServer:
 
         @app.post("/api/reload-engine")
         async def reload_engine():
-            success, message = ctrl.reload_engine()
+            import asyncio
+            loop = asyncio.get_event_loop()
+            success, message = await loop.run_in_executor(
+                None, ctrl.reload_engine
+            )
             if not success:
                 raise HTTPException(status_code=500, detail=message)
             return {"status": "ok", "message": message}