Inside ASGI The Engine Behind Modern Python Web Frameworks
Talkat PythonAsia 2026 · on Sunday, 2026-03-22· at 10:30· Yuchengco Hall 4th Flr. Y409 (Workshop Room 2)·
summary
ASGI is a 2016 specification that turns HTTP and WebSocket traffic into an event stream so a single thread can handle thousands of concurrent connections (the C10K problem) using Python async (asyncio in 3.4, async/await in 3.5). Servers like Uvicorn and Hypercorn own the event loop, build a scope dict, and hand apps two async callables—receive/send callables—so frameworks (Starlette, FastAPI) implement that contract. Middleware is plain function composition that can short‑circuit, log, or trace requests; the spec is stable and battle‑tested.
AI-written summary · about
chapters (14)
- 0:00ASGI introduction
- 1:08WSGI to ASGI evolution
- 7:19ASGI specification
- 10:34ASGI application contract
- 13:54ASGI event stream
- 17:09ASGI server ownership
- 19:36Server back pressure
- 22:04ASGI middleware
- 24:13Frameworks over ASGI
- 25:17ASGI future
- 26:23Q&A 1
- 27:43Q&A 2
- 29:30Q&A 3
- 31:04Closing
related talks
26mInside web framework: intro to the ASGI spec, middleware and apps
18mFrom WSGI to ASGI - Django 3.0
47mASGI in depth
31mHey, Python-Web-Community! What's going on?
32mSync vs. Async in Python: Tools, Benchmarks, and ASGI/WSGI Explained
24mA Brief History of Python Web Frameworks
55mKeynote: The Natural State of Computers
31mFastAPI Internals - How does it work?