PyPI · #46 most downloaded on PyPI

uvicorn

0.54.0493M downloads/moKludex/uvicorn ↗New releases in your daily digest, changelog included.

The lightning-fast ASGI server.

Last release 9 days ago
25 Sep 2026
Ships fairly regularly
a new release about every 3 weeks
Nearly every release is documented
notes for 60 of the last 60 stable releases
1 version withdrawn
withdrawn after publishing
9 years old
204 releases · first in 2017

Release timeline

204 releases since 2017

2017201920212023

Releases

0.54.025 Sept 2026
📨 Send metadata after the response body
📨 Send metadata after the response body

uvicorn 0.54.0 adds response trailers and 103 Early Hints to its experimental HTTP/2 implementation through zttp.

uv add uvicorn==0.54.0 "zttp>=0.0.34"

Send HTTP/2 response trailers (#3146). The ASGI http.response.trailers extension lets applications send metadata, such as checksums, after the response body. Clients must send TE: trailers to receive them. Multiple trailer messages are combined before completing the response.

HTTP/2 remains experimental and opt-in. Enable it with --http zttp --http2. Upgrade-based h2c and WebSockets over HTTP/2 remain unsupported.

💡 Hint at resources before the final response

Send 103 Early Hints over HTTP/2 (#3137). Applications can use the ASGI http.response.early_hint extension to send resource hints before the final response. Each supplied link becomes a separate Link header.

Full changelog: 0.53.0...0.54.0
Open source →
Additional notes2 sources agree
HTTP/2 support remains experimental. Install zttp>=0.0.34 and enable it with --http zttp --http2 .

Added

Add HTTP/2 response trailers through the ASGI http.response.trailers extension. Clients must send TE: trailers to receive them ( #3146 )

Add HTTP/2 103 Early Hints through the ASGI http.response.early_hint extension ( #3137 )

One column per quarter.

0.53.014 Sept 2026

uvicorn 0.53.0 adds experimental HTTP/2 through zttp , alongside a new zuvloop integration and connection-handling improvements.

🌐 Opt-in HTTP/2 support

uvicorn 0.53.0 adds experimental HTTP/2 through zttp, alongside a new zuvloop integration and connection-handling improvements.

uv add uvicorn==0.53.0

Serve HTTP/1.1 and HTTP/2 with zttp (#2982, #3101). Install zttp, then enable HTTP/2 with --http zttp --http2. Uvicorn negotiates HTTP/2 over TLS with ALPN and supports cleartext prior knowledge.
HTTP/2 remains experimental. Upgrade-based h2c and WebSockets over HTTP/2 are not supported.

⚙️ More event loop choice

Run Uvicorn with zuvloop (#3104). Install zuvloop separately and select it explicitly with --loop zuvloop on CPython 3.14 or newer.

🛡️ More reliable connections and proxies

Honor Connection: close token lists (#3103). Uvicorn now parses comma-separated tokens case-insensitively across HTTP implementations.
Trust IPv6 loopback proxies by default (#3119). The default FORWARDED_ALLOW_IPS value now includes ::1.
Keep upgraded WebSockets alive (#3107). Uvicorn cancels the HTTP keep-alive timer when the connection becomes a WebSocket.

Full changelog: 0.52.4...0.53.0

Open source →

Additional notes2 sources agree

This release adds experimental HTTP/2 support through zttp . Enable it with --http zttp --http2 . Upgrade-based h2c and WebSockets over HTTP/2 are not supported.

Added

Add experimental HTTP/2 support through zttp ( #2982 , #3101 )
Add support for zuvloop ( #3104 )

Fixed

Handle comma-separated, case-insensitive Connection: close tokens across HTTP implementations ( #3103 )
Trust IPv6 loopback in the default FORWARDED_ALLOW_IPS value ( #3119 )
Cancel the HTTP keep-alive timer when upgrading to WebSocket ( #3107 )

Open source →

0.52.419 Aug 20263 sources agree

Remove duplicate Date headers from accepted WebSocket handshakes with websockets-sansio

Fixed

Remove duplicate Date headers from accepted WebSocket handshakes with websockets-sansio (#3078)

Full Changelog: 0.52.3...0.52.4

Open source →

0.52.313 Aug 20263 sources agree

Update zttp to 0.0.24 and use its combined receive path, improving HTTP/1.1 request parsing performance

Changed

Update zttp to 0.0.24 and use its combined receive path, improving HTTP/1.1 request parsing performance (#3067)

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.52.2...0.52.3

Open source →

Additional notes

Changed

Update zttp to 0.0.24 and use its combined receive path, improving HTTP/1.1 request parsing performance (#3067)

Full Changelog: 0.52.2...0.52.3

Open source →

0.52.213 Aug 20263 sources agree

Update zttp to 0.0.22, fixing bodyless request receives and improving HTTP/1 request parsing performance

Fixed

Update zttp to 0.0.22, fixing bodyless request receives and improving HTTP/1 request parsing performance (#3063)

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.52.1...0.52.2

Open source →

Additional notes

Fixed

Update zttp to 0.0.22, fixing bodyless request receives and improving HTTP/1 request parsing performance (#3063)

Full Changelog: 0.52.1...0.52.2

Open source →

0.52.11 Aug 20263 sources agree

Complete the closing handshake on server-initiated WebSocket closes in the websockets-sansio and wsproto implementations, waiting for the client's clo

Fixed

Complete the closing handshake on server-initiated WebSocket closes in the websockets-sansio and wsproto implementations, waiting for the client's close reply with a 10 second timeout instead of resetting the connection (#3053)
Add missing write flow control to the websockets-sansio implementation, preventing data truncation on server-initiated closes with large in-flight payloads (#3048)
Handle connection loss while a WebSocket write is waiting on backpressure (#3050)
Remove duplicate Content-Type and Content-Length headers from WebSocket denial responses on the websockets-sansio implementation, and deliver non-UTF-8 denial bodies intact (#3041)

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.52.0...0.52.1

Open source →

0.52.029 Jul 20263 sources agree

This release adds an experimental HTTP/1.1 implementation backed by zttp, a sans-IO HTTP parser I've been developing on the side: a core written in Zi

This release adds an experimental HTTP/1.1 implementation backed by zttp, a sans-IO HTTP parser I've been developing on the side: a core written in Zig, with bindings to Python. It has been running under a fuzzer for some weeks now, and has been through multiple rounds of security auditing.

It is still experimental, so don't put it in front of production traffic yet. Try it with --http zttp, and please send any feedback to the issue tracker.

Added

Add an experimental zttp HTTP/1.1 implementation, selectable with --http zttp (#2979)

Fixed

Keep non-ASCII WebSocket request headers intact with websockets 17.0, which encodes them with ISO-8859-1 (#3036)

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.51.0...0.52.0

Open source →

0.51.08 Jul 2026

Restart workers with overlap on SIGHUP for near-zero-downtime reloads by @Kludex in https://github.com/Kludex/uvicorn/pull/3025

What's Changed

Restart workers with overlap on SIGHUP for near-zero-downtime reloads by @Kludex in https://github.com/Kludex/uvicorn/pull/3025
Remove colorama from the standard extra by @Kludex in https://github.com/Kludex/uvicorn/pull/3027

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.50.2...0.51.0

Open source →

Additional notes

What's Changed

Restart workers with overlap on SIGHUP for near-zero-downtime reloads by @Kludex in #3025
Remove colorama from the standard extra by @Kludex in #3027

Full Changelog: 0.50.2...0.51.0

Open source →

Additional notes2 sources agree

Added

Restart workers one at a time on SIGHUP , bringing each replacement up before retiring the old worker, so reloads no longer drop requests (#3025)

Removed

Remove colorama from the standard extra (#3027)

Open source →

0.50.26 Jul 2026

Require websockets>=13.0 for the default sansio implementation by @Kludex in #3021

What's Changed

Require websockets>=13.0 for the default sansio implementation by @Kludex in #3021

Full Changelog: 0.50.1...0.50.2

Open source →

Additional notes

What's Changed

Require websockets>=13.0 for the default sansio implementation by @Kludex in https://github.com/Kludex/uvicorn/pull/3021

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.50.1...0.50.2

Open source →

Additional notes2 sources agree

Fixed

Require websockets>=13.0 , which the default websockets-sansio implementation needs (#3021)

Open source →

0.50.16 Jul 2026

Split comma-separated Sec-WebSocket-Protocol values in the websockets-sansio implementation by @Aayush7352 in #3019

What's Changed

Split comma-separated Sec-WebSocket-Protocol values in the websockets-sansio implementation by @Aayush7352 in #3019

New Contributors

@Aayush7352 made their first contribution in #3019

Full Changelog: 0.50.0...0.50.1

Open source →

Additional notes

What's Changed

Split comma-separated Sec-WebSocket-Protocol values in the websockets-sansio implementation by @Aayush7352 in https://github.com/Kludex/uvicorn/pull/3019

New Contributors

@Aayush7352 made their first contribution in https://github.com/Kludex/uvicorn/pull/3019

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.50.0...0.50.1

Open source →

Additional notes2 sources agree

Fixed

Split comma-separated Sec-WebSocket-Protocol values in the websockets-sansio implementation (#3019)

Open source →

0.50.04 Jul 2026Deprecated

Deprecate the legacy websockets implementation and default auto to websockets-sansio by @Kludex in #2985

What's Changed

Memoize trusted host checks to avoid re-parsing the client IP per request by @Kludex in #2970
Cache the asgi scope sub-dict per connection by @Kludex in #2976
Build a fresh asgi scope dict per request by @Kludex in #2977
Replace click.style with an internal ANSI style helper by @Kludex in #2981
Avoid copying single-frame WebSocket payloads in websockets-sansio by @Kludex in #2983
Deprecate the legacy websockets implementation and default auto to websockets-sansio by @Kludex in #2985
Exit with a dedicated code on startup failure and stop the supervisor when a worker can't boot by @Kludex in #3001
Skip the eager app import in the parent when spawning workers by @Kludex in #3012

Full Changelog: 0.49.0...0.50.0

Open source →

Additional notes

What's Changed

Memoize trusted host checks to avoid re-parsing the client IP per request by @Kludex in https://github.com/Kludex/uvicorn/pull/2970
Cache the asgi scope sub-dict per connection by @Kludex in https://github.com/Kludex/uvicorn/pull/2976
Build a fresh asgi scope dict per request by @Kludex in https://github.com/Kludex/uvicorn/pull/2977
Replace click.style with an internal ANSI style helper by @Kludex in https://github.com/Kludex/uvicorn/pull/2981
Avoid copying single-frame WebSocket payloads in websockets-sansio by @Kludex in https://github.com/Kludex/uvicorn/pull/2983
Deprecate the legacy websockets implementation and default auto to websockets-sansio by @Kludex in https://github.com/Kludex/uvicorn/pull/2985
Exit with a dedicated code on startup failure and stop the supervisor when a worker can't boot by @Kludex in https://github.com/Kludex/uvicorn/pull/3001
Skip the eager app import in the parent when spawning workers by @Kludex in https://github.com/Kludex/uvicorn/pull/3012

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.49.0...0.50.0

Open source →

Additional notes2 sources agree

If you use WebSockets, note that --ws auto now picks the websockets-sansio implementation. You shouldn't need it, but you can pin --ws websockets to get the deprecated legacy one back.

Changed

Exit with the dedicated code 3 on any startup failure: app loading, socket bind and lifespan startup errors previously exited with a mix of 0, 1 and 3 (#3001)
Stop the multiprocess supervisor when a worker exits with code 3 instead of restarting it forever (#3001)
Default --ws auto to websockets-sansio when websockets is installed (#2985)
Skip the eager app import in the parent process with --reload or --workers , fixing a memory regression introduced in 0.47.0 (#3012)
Build a fresh asgi scope dict per request (#2977)
Cache the asgi scope sub-dict per connection (#2976)
Avoid copying single-frame WebSocket payloads in websockets-sansio (#2983)
Memoize trusted host checks in ProxyHeadersMiddleware (#2970)
Replace click.style with an internal ANSI style helper (#2981)

Deprecated

Deprecate the legacy websockets implementation; use websockets-sansio or wsproto instead (#2985)

Open source →

0.49.03 Jun 2026

Bump httptools minimum version to 0.8.0 by @Kludex in #2962

What's Changed

Bump httptools minimum version to 0.8.0 by @Kludex in #2962
Consume duplicate forwarding headers in ProxyHeadersMiddleware (reverses the 0.48.0 behavior of ignoring them) by @Kludex in #2971

Full Changelog: 0.48.0...0.49.0

Open source →

Additional notes

What's Changed

Bump httptools minimum version to 0.8.0 by @Kludex in https://github.com/Kludex/uvicorn/pull/2962
Consume duplicate forwarding headers in ProxyHeadersMiddleware (reverses the 0.48.0 behavior of ignoring them) by @Kludex in https://github.com/Kludex/uvicorn/pull/2971

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.48.0...0.49.0

Open source →

Additional notes2 sources agree

Changed

Bump httptools minimum version to 0.8.0 (#2962)
Consume duplicate forwarding headers in ProxyHeadersMiddleware (reverses the 0.48.0 behavior of ignoring them) (#2971)

Open source →

0.48.024 May 2026

Default ssl_ciphers to None and use OpenSSL defaults by @Kludex in https://github.com/Kludex/uvicorn/pull/2940

What's Changed

Default ssl_ciphers to None and use OpenSSL defaults by @Kludex in https://github.com/Kludex/uvicorn/pull/2940
Ignore duplicate forwarding headers in ProxyHeadersMiddleware by @Kludex in https://github.com/Kludex/uvicorn/pull/2944

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.47.0...0.48.0

Open source →

Additional notes2 sources agree

Changed

Default ssl_ciphers to None and use OpenSSL defaults (#2940)

Fixed

Ignore duplicate forwarding headers in ProxyHeadersMiddleware (#2944)

Open source →

0.47.014 May 2026

Eagerly import the ASGI app in the parent process by @Kludex in https://github.com/Kludex/uvicorn/pull/2919

What's Changed

Eagerly import the ASGI app in the parent process by @Kludex in https://github.com/Kludex/uvicorn/pull/2919
Add ssl_context_factory for custom SSLContext configuration by @Kludex in https://github.com/Kludex/uvicorn/pull/2920
Treat fd=0 as a valid file descriptor with reload/workers by @eltoder in https://github.com/Kludex/uvicorn/pull/2927

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.46.0...0.47.0

Open source →

Additional notes2 sources agree

Added

Add ssl_context_factory for custom SSLContext configuration (#2920)

Changed

Eagerly import the ASGI app in the parent process (#2919)

Fixed

Treat fd=0 as a valid file descriptor with reload/workers (#2927)

Open source →

0.46.023 Apr 2026

Support ws_max_size in wsproto implementation by @Kludex in https://github.com/Kludex/uvicorn/pull/2915

What's Changed

Support ws_max_size in wsproto implementation by @Kludex in https://github.com/Kludex/uvicorn/pull/2915
Support ws_ping_interval and ws_ping_timeout in wsproto implementation by @Kludex in https://github.com/Kludex/uvicorn/pull/2916
Use bytearray for incoming WebSocket message buffer in websockets-sansio by @Kludex in https://github.com/Kludex/uvicorn/pull/2917

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.45.0...0.46.0

Open source →

Additional notes2 sources agree

Added

Support ws_max_size in wsproto implementation (#2915)
Support ws_ping_interval and ws_ping_timeout in wsproto implementation (#2916)

Changed

Use bytearray for incoming WebSocket message buffer in websockets-sansio (#2917)

Open source →

0.45.021 Apr 2026

Preserve forwarded client ports in proxy headers middleware by @Kludex in https://github.com/Kludex/uvicorn/pull/2903

What's Changed

Preserve forwarded client ports in proxy headers middleware by @Kludex in https://github.com/Kludex/uvicorn/pull/2903
Accept os.PathLike for log_config by @Kludex in https://github.com/Kludex/uvicorn/pull/2905
Accept log_level strings case-insensitively by @Kludex in https://github.com/Kludex/uvicorn/pull/2907
Raise helpful ImportError when PyYAML is missing for YAML log config by @Kludex in https://github.com/Kludex/uvicorn/pull/2906
Revert empty context for ASGI runs by @Kludex in https://github.com/Kludex/uvicorn/pull/2911
Add --reset-contextvars flag to isolate ASGI request context by @Kludex in https://github.com/Kludex/uvicorn/pull/2912
Revert "Emit http.disconnect on server shutdown for streaming responses" (#2829) by @Kludex in https://github.com/Kludex/uvicorn/pull/2913

New Contributors

@Krishnachaitanyakc made their first contribution in https://github.com/Kludex/uvicorn/pull/2870

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.44.0...0.45.0

Open source →

Additional notes2 sources agree

Added

Add --reset-contextvars flag to isolate ASGI request context (#2912)
Accept os.PathLike for log_config (#2905)
Accept log_level strings case-insensitively (#2907)

Changed

Revert "Emit http.disconnect on server shutdown for streaming responses" (#2913)
Revert "Explicitly start ASGI run with empty context" (#2911)

Fixed

Preserve forwarded client ports in proxy headers middleware (#2903)
Raise helpful ImportError when PyYAML is missing for YAML log config (#2906)

Open source →

0.44.06 Apr 2026

Implement websocket keepalive pings for websockets-sansio by @Kludex in https://github.com/Kludex/uvicorn/pull/2888

What's Changed

Implement websocket keepalive pings for websockets-sansio by @Kludex in https://github.com/Kludex/uvicorn/pull/2888

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.43.0...0.44.0

Open source →

Additional notes2 sources agree

Added

Implement websocket keepalive pings for websockets-sansio (#2888)

Open source →

0.43.03 Apr 2026

Emit http.disconnect ASGI receive() event on server shutting down for streaming responses

Changed

Emit http.disconnect ASGI receive() event on server shutting down for streaming responses (#2829)
Use native context parameter for create_task on Python 3.11+ (#2859)
Drop cast in ASGI types (#2875)

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.42.0...0.43.0

Open source →

Additional notes2 sources agree

You can quit Uvicorn now. We heard you, @pamelafox - all 47 of your Ctrl+C's (thanks for flagging it, and thanks to @tiangolo for the fix 🙏). See the tweet .

Changed

Emit http.disconnect ASGI receive() event on server shutting down for streaming responses (#2829)
Use native context parameter for create_task on Python 3.11+ (#2859)
Drop cast in ASGI types (#2875)

Open source →

0.42.016 Mar 20263 sources agree

Use bytearray for request body accumulation to avoid O(n^2) allocation on fragmented bodies

Changed

Use bytearray for request body accumulation to avoid O(n^2) allocation on fragmented bodies (#2845)

Fixed

Escape brackets and backslash in httptools HEADER_RE regex (#2824)
Fix multiple issues in websockets sans-io implementation (#2825)

New Contributors

@bysiber made their first contribution in https://github.com/Kludex/uvicorn/pull/2825

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.41.0...0.42.0

Open source →

0.41.016 Feb 20263 sources agree

Add --limit-max-requests-jitter to stagger worker restarts

Added

Add --limit-max-requests-jitter to stagger worker restarts (#2707)
Add socket path to scope["server"] (#2561)

Changed

Rename LifespanOn.error_occured to error_occurred (#2776)

Fixed

Ignore permission denied errors in watchfiles reloader (#2817)
Ensure lifespan shutdown runs when should_exit is set during startup (#2812)
Reduce the log level of 'request limit exceeded' messages (#2788)

New Contributors

@t-kawasumi made their first contribution in https://github.com/Kludex/uvicorn/pull/2776
@fardyn made their first contribution in https://github.com/Kludex/uvicorn/pull/2800
@ewie made their first contribution in https://github.com/Kludex/uvicorn/pull/2807
@shevron made their first contribution in https://github.com/Kludex/uvicorn/pull/2788
@jonashaag made their first contribution in https://github.com/Kludex/uvicorn/pull/2707

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.40.0...0.41.0

Open source →

0.40.021 Dec 2025

Drop Python 3.9 by @Kludex in https://github.com/Kludex/uvicorn/pull/2772

What's Changed

Drop Python 3.9 by @Kludex in https://github.com/Kludex/uvicorn/pull/2772

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.39.0...0.40.0

Open source →

Additional notes2 sources agree

Remove

Drop support for Python 3.9 (#2772)

Open source →

0.39.021 Dec 2025

explicitly start ASGI run with empty context by @pmeier in https://github.com/Kludex/uvicorn/pull/2742

What's Changed

explicitly start ASGI run with empty context by @pmeier in https://github.com/Kludex/uvicorn/pull/2742
fix(websockets): Send close frame on ASGI return by @Kludex in https://github.com/Kludex/uvicorn/pull/2769

New Contributors

@pmeier made their first contribution in https://github.com/Kludex/uvicorn/pull/2742

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.38.0...0.39.0

Open source →

Additional notes2 sources agree

Fixed

Send close frame on ASGI return for WebSockets (#2769)
Explicitly start ASGI run with empty context (#2742)

Open source →

0.38.018 Oct 2025

Support Python 3.14 by @Kludex in https://github.com/Kludex/uvicorn/pull/2723

What's Changed

Support Python 3.14 by @Kludex in https://github.com/Kludex/uvicorn/pull/2723

New Contributors

@NGANAMODEIJunior made their first contribution in https://github.com/Kludex/uvicorn/pull/2713

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.37.0...0.38.0

Open source →

Additional notes2 sources agree

Added

Support Python 3.14 (#2723)

Open source →

0.37.023 Sept 2025

Add --timeout-worker-healthcheck setting by @Kludex in https://github.com/Kludex/uvicorn/pull/2711

What's Changed

Add --timeout-worker-healthcheck setting by @Kludex in https://github.com/Kludex/uvicorn/pull/2711
Add os.PathLike[str] type to ssl_ca_certs by @rnv812 in https://github.com/Kludex/uvicorn/pull/2676

New Contributors

@LincolnPuzey made their first contribution in https://github.com/Kludex/uvicorn/pull/2669
@rnv812 made their first contribution in https://github.com/Kludex/uvicorn/pull/2676

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.36.1...0.37.0

Open source →

Additional notes2 sources agree

Added

Add --timeout-worker-healthcheck option (#2711)
Add os.PathLike[str] type to ssl_ca_certs (#2676)

Open source →

0.36.123 Sept 2025

Raise an exception when calling removed Config.setup_event_loop() by @Kludex in https://github.com/Kludex/uvicorn/pull/2709

What's Changed

Raise an exception when calling removed Config.setup_event_loop() by @Kludex in https://github.com/Kludex/uvicorn/pull/2709

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.36.0...0.36.1

Open source →

Additional notes2 sources agree

Fixed

Raise an exception when calling removed Config.setup_event_loop() (#2709)

Open source →

0.36.020 Sept 2025

Support custom IOLOOPs by @gnir-work in https://github.com/Kludex/uvicorn/pull/2435

Added

Support custom IOLOOPs by @gnir-work in https://github.com/Kludex/uvicorn/pull/2435
Allow to provide importable string in --http, --ws and --loop by @Kludex in https://github.com/Kludex/uvicorn/pull/2658

New Contributors

@gnir-work made their first contribution in https://github.com/Kludex/uvicorn/pull/2435
@musicinmybrain made their first contribution in https://github.com/Kludex/uvicorn/pull/2659
@secrett2633 made their first contribution in https://github.com/Kludex/uvicorn/pull/2684

Full Changelog: https://github.com/Kludex/uvicorn/compare/0.35.0...0.36.0

Open source →

Additional notes2 sources agree

Added

Support custom IOLOOPs (#2435)
Allow to provide importable string in --http , --ws and --loop (#2658)

Open source →

0.35.028 Jun 2025

Add WebSocketsSansIOProtocol by @Kludex in https://github.com/encode/uvicorn/pull/2540

Added

Add WebSocketsSansIOProtocol by @Kludex in https://github.com/encode/uvicorn/pull/2540

Changed

Refine help message for option --proxy-headers by @zhangyoufu in https://github.com/encode/uvicorn/pull/2653

New Contributors

@zhangyoufu made their first contribution in https://github.com/encode/uvicorn/pull/2653

Full Changelog: https://github.com/encode/uvicorn/compare/0.34.3...0.35.0

Open source →

Additional notes2 sources agree

Added

Add WebSocketsSansIOProtocol (#2540)

Changed

Refine help message for option --proxy-headers (#2653)

Open source →

0.34.31 Jun 2025

Don't include cwd() when non-empty --reload-dirs is passed by @stinovlas in https://github.com/encode/uvicorn/pull/2598

What's Changed

Don't include cwd() when non-empty --reload-dirs is passed by @stinovlas in https://github.com/encode/uvicorn/pull/2598
Apply get_client_addr formatting to WebSocket logging by @Harry-Lees in https://github.com/encode/uvicorn/pull/2636
chore: improve type hints by @waketzheng in https://github.com/encode/uvicorn/pull/2638

New Contributors

@stinovlas made their first contribution in https://github.com/encode/uvicorn/pull/2598
@LifeLex made their first contribution in https://github.com/encode/uvicorn/pull/2621
@Harry-Lees made their first contribution in https://github.com/encode/uvicorn/pull/2636
@waketzheng made their first contribution in https://github.com/encode/uvicorn/pull/2638

Full Changelog: https://github.com/encode/uvicorn/compare/0.34.2...0.34.3

Open source →

Additional notes2 sources agree

Fixed

Don't include cwd() when non-empty --reload-dirs is passed (#2598)
Apply get_client_addr formatting to WebSocket logging (#2636)

Open source →

0.34.219 Apr 2025

Flush the stdout buffer on Windows to trigger reload by @jamesh1999 in https://github.com/encode/uvicorn/pull/2604

What's Changed

Flush the stdout buffer on Windows to trigger reload by @jamesh1999 in https://github.com/encode/uvicorn/pull/2604

New Contributors

@jamesh1999 made their first contribution in https://github.com/encode/uvicorn/pull/2604

Full Changelog: https://github.com/encode/uvicorn/compare/0.34.1...0.34.2

Open source →

Additional notes2 sources agree

Fixed

Flush stdout buffer on Windows to trigger reload (#2604)

Open source →

0.34.113 Apr 2025Deprecated

Deprecate ServerState in the main module by @Kludex in https://github.com/encode/uvicorn/pull/2581

What's Changed

Deprecate ServerState in the main module by @Kludex in https://github.com/encode/uvicorn/pull/2581

New Contributors

@RakhimovRamis made their first contribution in https://github.com/encode/uvicorn/pull/2567
@carlwgeorge made their first contribution in https://github.com/encode/uvicorn/pull/2590

Full Changelog: https://github.com/encode/uvicorn/compare/0.34.0...0.34.1

Open source →

Additional notes2 sources agree

Deprecated

Deprecate ServerState in the main module (#2581)

Open source →

0.34.015 Dec 2024

Add content-length to 500 response in wsproto by @Kludex in https://github.com/encode/uvicorn/pull/2542

What's Changed

Add content-length to 500 response in wsproto by @Kludex in https://github.com/encode/uvicorn/pull/2542
Drop Python 3.8 by @Kludex in https://github.com/encode/uvicorn/pull/2543

Full Changelog: https://github.com/encode/uvicorn/compare/0.33.0...0.34.0

Open source →

Additional notes2 sources agree

Added

Add content-length to 500 response in wsproto implementation (#2542)

Removed

Drop support for Python 3.8 (#2543)

Open source →

0.33.014 Dec 2024

Remove WatchGod by @Kludex in https://github.com/encode/uvicorn/pull/2536

What's Changed

Remove WatchGod by @Kludex in https://github.com/encode/uvicorn/pull/2536

New Contributors

@bwells made their first contribution in https://github.com/encode/uvicorn/pull/2491
@tback made their first contribution in https://github.com/encode/uvicorn/pull/2528

Full Changelog: https://github.com/encode/uvicorn/compare/0.32.1...0.33.0

Open source →

Additional notes2 sources agree

Removed

Remove WatchGod support for --reload (#2536)

Open source →

0.32.120 Nov 2024

Enable httptools lenient data by @vvanglro in https://github.com/encode/uvicorn/pull/2488

What's Changed

Enable httptools lenient data by @vvanglro in https://github.com/encode/uvicorn/pull/2488
Drop ASGI spec version to 2.3 on HTTP scope by @Kludex in https://github.com/encode/uvicorn/pull/2513

Full Changelog: https://github.com/encode/uvicorn/compare/0.32.0...0.32.1

Open source →

Additional notes2 sources agree

Fixed

Drop ASGI spec version to 2.3 on HTTP scope (#2513)
Enable httptools lenient data on httptools >= 0.6.3 (#2488)

Open source →

0.32.015 Oct 20243 sources agree

Warn when max_request_limit is exceeded

Added

Officially support Python 3.13 (#2482)
Warn when max_request_limit is exceeded (#2430)

Full Changelog: https://github.com/encode/uvicorn/compare/0.31.1...0.32.0

Open source →

0.31.19 Oct 20243 sources agree

Support WebSockets 0.13.1 #2471

Fixed

Support WebSockets 0.13.1 #2471
Restore support for [*] in trusted hosts #2480
Add PathLike[str] type hint for ssl_keyfile #2481

Full Changelog: https://github.com/encode/uvicorn/compare/0.31.0...0.31.1

Open source →

0.31.027 Sept 20243 sources agree

Improve ProxyHeadersMiddleware (#2468) and (#2231):

Added

Improve ProxyHeadersMiddleware (#2468) and (#2231):

Fix the host for requests from clients running on the proxy server itself.
Fallback to host that was already set for empty x-forwarded-for headers.
Also allow specifying IP Networks as trusted hosts. This greatly simplifies deployments on docker swarm/Kubernetes, where the reverse proxy might have a dynamic IP.
- This includes support for IPv6 Address/Networks.

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.6...0.31.0

Open source →

0.30.613 Aug 2024

Don't warn when upgrade is not WebSocket and depedencies are installed

Fixed

Don't warn when upgrade is not WebSocket and depedencies are installed (#2360)

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.5...0.30.6

Open source →

Additional notes2 sources agree

Fixed

Don't warn when upgrade is not WebSocket and dependencies are installed (#2360)

Open source →

0.30.52 Aug 20243 sources agree

Don't close connection before receiving body on H11

Fixed

Don't close connection before receiving body on H11 (#2408)

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.4...0.30.5

Open source →

0.30.431 Jul 20243 sources agree

Close connection when h11 sets client state to MUST_CLOSE #2375

Fixed

Close connection when h11 sets client state to MUST_CLOSE #2375

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.3...0.30.4

Open source →

0.30.320 Jul 20243 sources agree

Suppress KeyboardInterrupt from CLI and programmatic usage

Fixed

Suppress KeyboardInterrupt from CLI and programmatic usage (#2384)
ClientDisconnect inherits from OSError instead of IOError (#2393)

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.2...0.30.3

Open source →

0.30.220 Jul 20243 sources agree

Add reason support to `websocket.disconnect` event

Added

Add reason support to websocket.disconnect event (#2324)

Fixed

Iterate subprocesses in-place on the process manager (#2373)

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.1...0.30.2

Open source →

0.30.12 Jun 20243 sources agree

Allow horizontal tabs \t in response header values

Fixed

Allow horizontal tabs \t in response header values (#2345)

Full Changelog: https://github.com/encode/uvicorn/compare/0.30.0...0.30.1

Open source →

0.30.028 May 2024Deprecated3 sources agree

Deprecate the uvicorn.workers module

Added

New multiprocess manager (#2183)
Allow ConfigParser or a io.IO[Any] on log_config (#1976)

Fixed

Suppress side effects of signal propagation (#2317)
Send content-length header on 5xx (#2304)

Deprecated

Deprecate the uvicorn.workers module (#2302)

Full Changelog: https://github.com/encode/uvicorn/compare/0.29.0...0.30.0

Open source →

0.29.020 Mar 2024

Cooperative signal handling by @maxfischer2781 in https://github.com/encode/uvicorn/pull/1600

Added

Cooperative signal handling by @maxfischer2781 in https://github.com/encode/uvicorn/pull/1600

Full Changelog: https://github.com/encode/uvicorn/compare/0.28.1...0.29.0

Open source →

Additional notes2 sources agree

Added

Cooperative signal handling (#1600)

Open source →

0.28.119 Mar 2024

Revert raise ClientDisconnected on HTTP

Fixed

Revert raise ClientDisconnected on HTTP (#2276)

Full Changelog: https://github.com/encode/uvicorn/compare/0.28.0...0.28.1

Open source →

Additional notes2 sources agree

Fixed

Revert raise ClientDisconnected on HTTP (#2276)

Open source →

0.28.09 Mar 2024

Raise ClientDisconnected on send() when client disconnected (#2220) 12/02/24

Added

Raise ClientDisconnected on send() when client disconnected (#2220) 12/02/24

Fixed

Except AttributeError on sys.stdin.fileno() for Windows IIS10 (#1947) 29/02/24
Use X-Forwarded-Proto for WebSockets scheme when the proxy provides it (#2258) 01/03/24

Full Changelog: https://github.com/encode/uvicorn/compare/0.27.1...0.28.0

Open source →

Additional notes2 sources agree

Added

Raise ClientDisconnected on send() when client disconnected (#2220)

Fixed

Except AttributeError on sys.stdin.fileno() for Windows IIS10 (#1947)
Use X-Forwarded-Proto for WebSockets scheme when the proxy provides it (#2258)

Open source →

0.27.110 Feb 2024

Fix spurious h11.LocalProtocolError errors when processing pipelined requests (#2243) 10/02/24

Fixed

Fix spurious h11.LocalProtocolError errors when processing pipelined requests (#2243) 10/02/24

Full Changelog: https://github.com/encode/uvicorn/compare/0.27.0.post1...0.27.1

Open source →

Additional notes2 sources agree

Fix spurious LocalProtocolError errors when processing pipelined requests (#2243)

Open source →

0.27.0.post129 Jan 20243 sources agree

Fix nav overrides for newer version of Mkdocs Material (#2233) 26/01/24

Fixed

Fix nav overrides for newer version of Mkdocs Material (#2233) 26/01/24

Full Changelog: https://github.com/encode/uvicorn/compare/0.27.0...0.27.0.post1

Open source →

0.27.022 Jan 2024

Raise ClientDisconnect(IOError) on send() when client disconnected (#2218) 19/01/24

Added

Raise ClientDisconnect(IOError) on send() when client disconnected (#2218) 19/01/24
Bump ASGI WebSocket spec version to 2.4 (#2221) 20/01/24

Full Changelog: https://github.com/encode/uvicorn/compare/0.26.0...0.27.0

Open source →

Additional notes2 sources agree

Added

Raise ClientDisconnect(IOError) on send() when client disconnected (#2218)
Bump ASGI WebSocket spec version to 2.4 (#2221)

Open source →

0.26.016 Jan 20243 sources agree

Update --root-path to include the root path prefix in the full ASGI path as per the ASGI spec (#2213) 16/01/24

Changed

Update --root-path to include the root path prefix in the full ASGI path as per the ASGI spec (#2213) 16/01/24
Use __future__.annotations on some internal modules (#2199) 16/01/24

Full Changelog: https://github.com/encode/uvicorn/compare/0.25.0...0.26.0

Open source →

0.25.020 Dec 2023

Support the WebSocket Denial Response ASGI extension (#1916) 17/12/23

Added

Support the WebSocket Denial Response ASGI extension (#1916) 17/12/23

Fixed

Allow explicit hidden file paths on --reload-include (#2176) 08/12/23
Properly annotate uvicorn.run() (#2158) 22/11/23

Full Changelog: https://github.com/encode/uvicorn/compare/0.24.0...0.25.0

Open source →

Additional notes2 sources agree

Added

Support the WebSocket Denial Response ASGI extension (#1916)

Fixed

Allow explicit hidden file paths on --reload-include (#2176)
Properly annotate uvicorn.run() (#2158)

Open source →

0.24.0.post16 Nov 20233 sources agree

Revert mkdocs-material from 9.1.21 to 9.2.6 (#2148) 05/11/23

Fixed

Revert mkdocs-material from 9.1.21 to 9.2.6 (#2148) 05/11/23

Open source →

0.24.04 Nov 2023

Support Python 3.12 (#2145) 04/11/23

Added

Support Python 3.12 (#2145) 04/11/23
Allow setting app via environment variable UVICORN_APP (#2106)

Full Changelog: https://github.com/encode/uvicorn/compare/0.23.2...0.24.0

Open source →

Additional notes2 sources agree

Added

Support Python 3.12 (#2145)
Allow setting app via environment variable UVICORN_APP (#2106)

Open source →

0.23.231 Jul 20233 sources agree

Maintain the same behavior of websockets from 10.4 on 11.0 (#2061) 30/07/23

Fixed

Maintain the same behavior of websockets from 10.4 on 11.0 (#2061) 30/07/23

Full Changelog: https://github.com/encode/uvicorn/compare/0.23.1...0.23.2

Open source →

0.23.118 Jul 20233 sources agree

Add typing_extensions for Python 3.10 and lower (#2053) 18/07/23

Fixed

Add typing_extensions for Python 3.10 and lower (#2053) 18/07/23

Full Changelog: https://github.com/encode/uvicorn/compare/0.23.0...0.23.1

Open source →

0.23.015 Jul 2023

Add --ws-max-queue parameter WebSockets (#2033) 10/07/23

Added

Add --ws-max-queue parameter WebSockets (#2033) 10/07/23

Removed

Drop support for Python 3.7 (#1996) 19/06/23
Remove asgiref as typing dependency (#1999) 08/06/23

Fixed

Set scope["scheme"] to ws or wss instead of http or https on ProxyHeadersMiddleware for WebSockets (#2043) 12/07/23

Changed

Raise ImportError on circular import (#2040) 09/07/23
Use logger.getEffectiveLevel() instead of logger.level to check if log level is TRACE (#1966) 01/06/23

Full Changelog: https://github.com/encode/uvicorn/compare/0.22.0...0.23.0

Open source →

Additional notes2 sources agree

Added

Add --ws-max-queue parameter WebSockets (#2033)

Removed

Drop support for Python 3.7 (#1996)
Remove asgiref as typing dependency (#1999)

Fixed

Set scope["scheme"] to ws or wss instead of http or https on ProxyHeadersMiddleware for WebSockets (#2043)

Changed

Raise ImportError on circular import (#2040)
Use logger.getEffectiveLevel() instead of logger.level to check if log level is TRACE (#1966)

Open source →

0.22.028 Apr 20233 sources agree

Add --timeout-graceful-shutdown parameter

Added

Add --timeout-graceful-shutdown parameter (#1950)
Handle SIGBREAK on Windows (#1909)

Fixed

Shutdown event is now being triggered on Windows when using hot reload (#1584)
--reload-delay is effectively used on the watchfiles reloader (#1930)

Full Changelog: https://github.com/encode/uvicorn/compare/0.21.1...0.22.0

Open source →

0.21.116 Mar 2023

Reset lifespan state on each request (#1903) 16/03/23

Fixed

Reset lifespan state on each request (#1903) 16/03/23

Open source →

Additional notes2 sources agree

Fixed

Reset lifespan state on each request (#1903)

Open source →

0.21.09 Mar 2023

Introduce lifespan state (#1818) 05/03/23

Added

Introduce lifespan state (#1818) 05/03/23
Allow headers to be sent as iterable on H11 implementation (#1782) 27/11/22
Improve discoverability when --port=0 is used (#1890) 09/03/23

Changed

Avoid importing h11 and pyyaml when not needed to improve import time (#1846) 07/02/23
Replace current native WSGIMiddleware implementation by a2wsgi (#1825) 16/01/23
Change default --app-dir from "." (dot) to "" (empty string) (#1835) 06/01/23

Fixed

Send code 1012 on shutdown for WebSockets (#1816) 06/01/23
Use surrogateescape to encode headers on websockets implementation (#1005) 12/12/22
Fix warning message on reload failure (#1784) 29/11/22

Full Changelog: https://github.com/encode/uvicorn/compare/0.20.0...0.21.0

Open source →

Additional notes2 sources agree

Added

Introduce lifespan state (#1818)
Allow headers to be sent as iterables on H11 implementation (#1782)
Improve discoverability when --port=0 is used (#1890)

Changed

Avoid importing h11 and pyyaml when not needed to improve import time (#1846)
Replace current native WSGIMiddleware implementation by a2wsgi (#1825)
Change default --app-dir from "." (dot) to "" (empty string) (#1835)

Fixed

Send code 1012 on shutdown for WebSockets (#1816)
Use surrogateescape to encode headers on websockets implementation (#1005)
Fix warning message on reload failure (#1784)

Open source →

0.20.020 Nov 2022

Check if handshake is completed before sending frame on wsproto shutdown

Added

Check if handshake is completed before sending frame on wsproto shutdown (#1737)
Add default headers to WebSockets implementations (#1606 & #1747) 28/10/22
Warn user when reload and workers flag are used together (#1731) 31/10/22

Fixed

Use correct WebSocket error codes on close (#1753) 20/11/22
Send disconnect event on connection lost for wsproto (#996) 29/10/22
Add SIGQUIT handler to UvicornWorker (#1710) 01/11/22
Fix crash on exist with "--uds" if socket doesn't exist (#1725) 27/10/22
Annotate CONFIG_KWARGS in UvicornWorker class (#1746) 31/10/22

Removed

Remove conditional on RemoteProtocolError.event_hint on wsproto (#1486) 31/10/22
Remove unused handle_no_connect on wsproto implementation (#1759) 17/11/22

Open source →

Additional notes2 sources agree

Added

Check if handshake is completed before sending frame on wsproto shutdown (#1737)
Add default headers to WebSockets implementations (#1606 & #1747)
Warn user when reload and workers flag are used together (#1731)

Fixed

Use correct WebSocket error codes on close (#1753)
Send disconnect event on connection lost for wsproto (#996)
Add SIGQUIT handler to UvicornWorker (#1710)
Fix crash on exist with "--uds" if socket doesn't exist (#1725)
Annotate CONFIG_KWARGS in UvicornWorker class (#1746)

Removed

Remove conditional on RemoteProtocolError.event_hint on wsproto (#1486)
Remove unused handle_no_connect on wsproto implementation (#1759)

Open source →

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uvicorn

Release timeline

Releases

📨 Send metadata after the response body

💡 Hint at resources before the final response

Added

🌐 Opt-in HTTP/2 support

⚙️ More event loop choice

🛡️ More reliable connections and proxies

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