Missing add_websocket_route() helper in root Starlette application class

[KACAH]

add_websocket_route() helper was removed from root Starlette application class in the following commit:

f99e11f#diff-3eb07c0eea72d98f1b844e07844c2a68b7c11c63956b67d5afdd9c7f79ab946fR8-L152

Why?

This method is still present in Router:

starlette/starlette/routing.py

Line 740 in edcc79e

def add_websocket_route(

So I assume it is still a valid API for adding new Websocket routes to an existing router.

[Urus1201]

add_websocket_route() was removed from the root Starlette application class as part of a deliberate API narrowing — the root class is being gradually simplified to not re-export convenience methods that properly belong on Router. The functionality itself is not gone.

Is Router.add_websocket_route() still valid?

Yes. The method lives on Router, and since Starlette.router is a public Router instance, you can call it directly:

from starlette.applications import Starlette

async def my_ws_handler(websocket):
    await websocket.accept()
    await websocket.send_text("hello")
    await websocket.close()

app = Starlette()
app.router.add_websocket_route("/ws", my_ws_handler)

This is functionally identical to the old app.add_websocket_route("/ws", my_ws_handler).

Alternative: declare routes at startup

The idiomatic Starlette pattern avoids imperative add_route calls entirely and declares routes up-front:

from starlette.applications import Starlette
from starlette.routing import WebSocketRoute

app = Starlette(routes=[
    WebSocketRoute("/ws", my_ws_handler),
])

This is preferred because routes are immutable after the ASGI lifecycle starts — dynamically adding routes post-startup can cause issues with route detection in certain ASGI middleware stacks.

Decorator style (still works)

If you prefer decorators, mount a sub-router:

from starlette.routing import Router
from starlette.websockets import WebSocket

ws_router = Router()

@ws_router.websocket_route("/ws")
async def my_ws_handler(websocket: WebSocket):
    await websocket.accept()
    ...

app = Starlette()
app.mount("/", ws_router)