ASGI

Traditional ASGI middleware only works with web-based transports (streamable-HTTP, SSE), not with the STDIO transport that most major MCP clients use. This forces developers to either wrap servers in complex workarounds or abandon middleware patterns.

uWSGI completely demised; Gunicorn losing async workload share; ASGI servers (uvicorn, Hypercorn) replace WSGI. Rust-based alternatives (Granian) emerging, fragmenting tooling ecosystem and forcing framework migrations.