Skip to main content

"SSE plugin for Starlette",

Project description

Server Sent Events for Starlette and FastAPI

PyPI Version Build Status Code Coverage



pip install sse-starlette


import asyncio
import uvicorn
from starlette.applications import Starlette
from starlette.routing import Route
from sse_starlette.sse import EventSourceResponse

async def numbers(minimum, maximum):
    for i in range(minimum, maximum + 1):
        await asyncio.sleep(0.9)
        yield dict(data=i)

async def sse(request):
    generator = numbers(1, 5)
    return EventSourceResponse(generator)

routes = [
    Route("/", endpoint=sse)

app = Starlette(debug=True, routes=routes)

if __name__ == "__main__":, host="", port=8000, log_level='info')


Caveat: SSE streaming does not work in combination with GZipMiddleware.

Be aware that for proper server shutdown your application must stop all running tasks (generators). Otherwise you might experience the following warnings at shutdown: Waiting for background tasks to complete. (CTRL+C to force quit).

Client disconnects need to be handled in your Request handler (see

async def endless(req: Request):
    async def event_publisher():
        i = 0
          while True:
              disconnected = await req.is_disconnected()
              if disconnected:
        "Disconnecting client {req.client}")
              i += 1
              yield dict(data=i)
              await asyncio.sleep(0.2)
"Disconnected from client {req.client}")
        except asyncio.CancelledError as e:
"Disconnected from client (via refresh/close) {req.client}")
          # Do any other cleanup, if any
          raise e
    return EventSourceResponse(event_publisher())

Run the tests:

make test


0.7.2 (2021-04-18)

  • refactoring: Github Actions introduced into build pipeline

0.6.2 (2020-12-19)

  • fix: correct shutdown signal handling in case of an endpoint which only yields sporadic messages

0.6.1 (2020-10-24)

  • updated example with proper error handling

0.6.0 (2020-10-24)

  • In case uvicorn is used: monkeypatch uvicorn signal-handler, in order to gracefully shutdown long-running handlers/generators.

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for sse-starlette, version 0.7.2
Filename, size File type Python version Upload date Hashes
Filename, size sse_starlette-0.7.2-py3-none-any.whl (7.3 kB) File type Wheel Python version py3 Upload date Hashes View
Filename, size sse-starlette-0.7.2.tar.gz (7.7 kB) File type Source Python version None Upload date Hashes View

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring DigiCert DigiCert EV certificate Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page