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PyPI · #744 most downloaded on PyPI
Engine.IO server and client for Python
Last release 1 months ago
30 Aug 2026
Ships fairly regularly
a new release about every 6 weeks
Nearly every release is documented
notes for 59 of the last 60 stable releases
Nothing withdrawn
no release was ever pulled
11 years old
148 releases · first in 2015
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One column per quarter.
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Prevent a race condition in the sync client's connection close handling #458 ( commit )
Cleaner WebSocket exit for Werkzeug #457 ( commit )
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Make sure client disconnects when write loop exits #455 ( commit )
Address flaky unit test #444 ( commit )
Stop using codecov service, since it has been failing for a long time ( commit )
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Prevent unnecessary resource allocations #441 ( commit )
Add zizmor to CI builds #437 ( commit )
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Document that a process can have only one custom JSON module ( commit )
Switch to Furo documentation template ( commit )
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Apply escaping rules when parsing cookie values ( commit )
Several minor improvements to the aiohttp integration #419 ( commit ) (thanks PaulWasTaken !)
Clarify logging behavior in documentation #421 ( commit ) (thanks ZipFile !)
Address deprecation warnings #422 ( commit )
Add 3.14 and pypy-3.11 CI builds ( commit )
Drop Python 3.8 and 3.9 from CI builds ( commit )
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Reset client queue upon disconnection #414 ( commit )
Support [''] in addition to '' in the cors_allowed_origins option #410 ( commit ) (thanks Wu Clan !)
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Support new monkey-patched gevent Queue class in the client #403 ( commit )
Better support of the ASGI spec when interpreting WebSocket events #405 ( commit ) (thanks Eric Zhang !)
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Accept empty binary values in the async server #404 ( commit )
Add SPDX license identifier #401 ( commit ) (thanks Marc Mueller !)
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Optimize packet parsing to avoid unnecessary calls to JSON parser #399 ( commit )
Pass environ as a second argument to callable option cors_allowed_origins #398 ( commit ) (thanks wft-swas !)
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Pass a reason argument to the disconnect handler #393 ( commit )
Add maxPayload to connection response #392 ( commit ) (thanks HeySMMReseller & HeySMMProvider !)
Client option to disable timestamps in connection URLs #386 ( commit )
Return disconnected sessions as 400 errors #391 ( commit )
Handle unicode errors in ASGI driver #389 ( commit )
Replaced deprecated get_event_loop with get_running_loop #384 ( commit )
Remove constructs required by older, now unsupported Python versions ( commit )
Switched to pyenv-asyncio for async unit tests ( commit )
Adopted unittest.mock.AsyncMock in async unit tests instead of homegrown version ( commit )
Removed tests dependency on unittest.TestCase base class ( commit )
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Reject requests with incorrect transport #367 ( commit )
Fixed runtime error when disconnecting all clients #368 ( commit )
More flexible handling of the ASGI path #359 ( commit )
Remove unused parameter in log message #377 ( commit )
Minor updates to the server and client documentation ( commit )
Add Python 3.13 CI builds ( commit )
Run tests with mocked eventlet to avoid 3.13 failures ( commit )
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Fix inverted shutdown logic in async service task #354 ( commit )
More robust WebSocket close detection in the sync client #346 ( commit )
Option to disable routing in ASGIApp #345 ( commit ) (thanks Rodja Trappe !)
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More robust handling of polling disconnects #254 ( commit )
Clearer client logs after disconnect #342 ( commit )
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Combine ssl_verify with other SSL options ( commit ) (thanks Simon Fonteneau !)
Hold references to background tasks to avoid garbage collection ( commit )
Clearer documentation for the max_http_buffer_size argument ( commit )
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Return consistent responses after Websocket connection ends ( commit )
Migrate Python package metadata to pyproject.toml ( commit )
Remove Python 3.7 from builds ( commit )
Internal code restructure (no functional changes) ( commit #1 ) ( commit #2 ) ( commit #3 ) ( commit #4 )
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Replace gevent-websocket with simple-websocket when using gevent ( commit )
Catch and log all errors that occur in event handlers ( commit )
Use daemon threads for background tasks also in the threaded client ( commit )
Silence exception on websocket exit when using uWSGI #330 ( commit )
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Added send_packet() method ( commit )
Fixed race condition when lots of connections are ended at the same time #328 ( commit )
Workaround for strange memory leak in Eventlet's Thread class #328 ( commit )
Use daemon threads for background tasks in threading mode ( commit )
Upgrade to pypy-3.9 in unit tests ( commit )
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Improvements in the connection rejected flow ( commit )
Better handling of Gunicorn threaded worker ( commit )
shutdown() method for the Engine.IO server ( commit )
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Configure eventlet's websocket max frame length #319 ( commit )
Remove old Python 2 syntax in super() calls ( commit )
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Prevent crash when closing simple-websocket connection #311 ( commit )
Fix server/client mixup in client docstrings #312 ( commit ) (thanks Sasja !)
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Allow configuring underlying websocket connection with custom options #293 ( commit ) (thanks Bruce Yu !)
Cancel all running tasks in async SIGINT handler #306 ( commit )
Handle unexpected WebSocket close frames sent by server #292 ( commit )
Close aiohttp session after a failed connection #307 ( commit )
Catch IOErrors from uWSGI and explicitly close the driver #301 ( commit ) (thanks June Oh !)
Recommend ASGI integration for Sanic in Documentation ( commit )
Fix documentation for max_http_buffer_size #310 ( commit ) (thanks Lawrence Ong !)
Add Python 3.11 to builds ( commit )
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Let companion ASGI app handle lifespan events #287 ( commit )
Use configured request timeout when making a WebSocket connection #286 ( commit ) (thanks jpfarias !)
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Handle ASGI lifespan when running with a secondary ASGI app #284 ( commit ) (thanks mozartilize !)
Update deprecated usage of asyncio.wait() #281 ( commit ) (thanks Ben Beasley !)
Better handling of queued WebSocket messages in uWSGI #256 ( commit )
Gracefully fail to decode empty packets #269 ( commit )
Only attempt to set an async signal handler once #276 ( commit )
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Option to use a callable for cors_allowed_origins #264 ( commit )
Close aiohttp session when disconnecting #272 ( commit )
Remove 3.6 and pypy-3.6 builds, add 3.10 and pypy-3.8 ( commit )
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Fix support for Sanic v21.9.0 and up ( commit ) (thanks 13g10n !)
Include example code in flake8 pass ( commit )
Remove unused version constant #262 ( commit 1 commit 2 )
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Backward incompatible change : Reject websocket messages larger than max_http_buffer_size #260 ( commit )
Enable or disable specific transports #259 ( commit ) (thanks Maciej Szeptuch !)
Option to disable the SIGINT handler in the client ( commit )
Support binary packets with zero length #257 ( commit )
Improve documentation on start_background_task() function ( commit )
Remove unsanitized client input from error messages #250 ( commit ) (thanks André Carvalho !)
Use plaintext Content-Type when using polling #248 ( commit ) (thanks Tobias !)
Return better error messages for client connection errors #243 ( commit )
Reuse the aiohttp client session on reconnects #226 ( commit )
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Support setting socketio_path to the root URL #242 ( commit )
Use the gevent selector to avoid 1024 file handle limitation of select #228 ( commit )
Pass reason when closing a WebSocket connection ( commit )
Improved project structure ( commit )
Remove executable permissions from files that lack shebang lines #240 ( commit ) (thanks Ben Beasley !)
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WebSocket support for threading mode ( commit )
Fixed CORS handling of scheme proxy server header #1501 ( commit )
Correct handling of static files when secondary WSGI/ASGI app is set #653 ( commit )
Remove outdated binary argument from example code ( commit )
Added Open Collective funding option ( commit )
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Change pingTimeout to 20 seconds to match JavaScript's Socket.IO 4.x releases ( commit )
Configure the JSON decoder for safer parsing ( commit ) (thanks Onno Kortmann )
Remove obsolete 'mock' dependency #218 ( commit ) (thanks Michał Górny !)
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Support for client to verify server with custom CA bundle ( commit ) (thanks Brandon Hastings !)
Report missing websocket client as an error in log #557 ( commit )
Remove asyncio client delay before attempting reconnection #622 ( commit )
Fix error handling for ASGI WebSocket errors #210 ( commit )
Fix logging of missing sid #1472 ( commit )
Change deprecated body_bytes in sanic to body #207 ( commit ) (thanks Alison Almeida !)
Remove references to Python 3.5 in the documentation #211 ( commit )
Added performance testing scripts ( commit )
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Implementation of the Engine.IO v4 protocol revision
v4 protocol: ping/ping reversal in the server ( commit )
v4 protocol: ping/ping reversal in the client ( commit )
v4 protocol: change max http buffer size to 1MB ( commit )
v4 protocol: do not set the io cookie by default ( commit )
v4 protocol: use EIO=4 in connection URL ( commit )
v4 protocol: new payload separator ( commit )
v4 protocol: new binary encoding format ( commit )
Use a sid generator algorithm similar to JavaScript's version of Socket.IO ( commit )
Ignore case when comparing transport argument against 'HTTP_UPGRADE' header ( commit ) (thanks Matthew Barry !)
Remove dependency on the six package ( commit )
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Catch more connection exceptions in the asyncio client #561 ( commit )
Revert "On Windows use SIGBREAK to break client" since the fix was not effective ( commit )
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Reject incorrect Engine.IO protocol versions ( commit )
Accept an initialized requests or aiohttp session object ( commit )
Handle ping interval and timeout given as strings #201 ( commit ) (thanks Akash Vibhute !)
Handle websocket connections without upgrade header #72 ( commit )
Catch broken pipes and OS errors in websocket thread #177 ( commit )
Expose ASGI scope in connect environ #192 ( commit ) (thanks Korijn van Golen !)
Emit ASGI lifespan shutdown event #200 ( commit )
Add option to set cookie SameSite and Secure settings. ( commit ) (thanks Billy Felton !)
Stop event loop when client is interrupted with Ctrl-C #197 ( commit )
Do not try to install signal handler if unsupported #199 ( commit ) (thanks Philippe !)
On Windows use SIGBREAK to break client #570 ( commit )
Client: handle error responses with invalid JSON #553 ( commit )
Added troubleshooting section to the documentation ( commit )
Move builds to GitHub actions ( commit )
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Improved signal handler for the async client #523 ( commit )
Add SameSite attribute to Socket.IO cookie #1344 ( commit )
Handle GeneratorExit exception appropriately #182 ( commit ) (thanks PaulWasTaken !)
Simplify asserts in unit tests ( commit )
Use pytest as test runner ( commit )
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Support direct WebSocket connections in ASGI server ( commit )
ASGI startup and shutdown lifespan handlers #169 ( commit ) (thanks avi !)
Improved handling of rejected connections ( commit )
Make client disconnects more robust #417 ( commit )
End WebSocket connection gracefully when user is intentionally disconnected #168 ( commit ) (thanks Mohammad Almoghrabi !)
Enable locking in websocket-client package #170 ( commit )
Correctly parse cookies with a "=" in their values #175 ( commit ) (thanks Ignacio Pascual !)
Removed references to Python 2.7 in the documentation ( commit )
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Correct handling of cookies in the client #162 ( commit )
Fixed infrequent race condition when upgrading from polling to WebSocket #160 ( commit )
Only add signal handler when client is created in main thread #163 ( commit )
More robust handling of a closing connection #164 ( commit )
More accurate logging documentation #158 ( commit )
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Last version to support Python 2
Detect unreported websocket closures in asyncio client #401 ( commit )
Initialize aiohttp when client connects directly through websocket #152 ( commit )
Initialize the client's SIGINT signal handler only if a client is created #147 ( commit )
Add better exception handling for errors thrown by the websocket-client package #155 ( commit ) (thanks Adam Grant !)
Missing timeout when closing websocket client connection #148 ( commit )
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Use aiohttp's WebSocket client #324 ( commit )
Support user created loops on the asyncio client #1065 ( commit )
Fix occasional server disconnect crashes #146 ( commit ) (thanks Dominik Winecki !)
Use X-Forwarded headers if present to verify origin ( commit )
Support async make_response function in ASGI driver #145 ( commit )
Support not having a sigint handler #143 ( commit ) (thanks Robin Christine Burr !)
Fix websocket exception handling on python2.7 #149 ( commit ) (thanks Payton Yao !)
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Added support for SSL connection to unverified host in the client. #137 ( commit ) (thanks sgaron-cse !)
Performance improvements in parsing long-polling payloads ( commit )
Prevent heavy CPU usage when decoding payloads ( commit )
Handle case where no original SIGINT handler existed and call signal.… #140 ( commit ) (thanks Robin Christine Burr !)
Accept any 2xx response as valid in the client #331 ( commit )
Avoid loop without yield when sockets are >60 #138 ( commit ) (thanks Gawen Arab !)
Configurable ping interval grace period #134 ( commit )
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Apply timeouts to all HTTP requests sent from the client #127 ( commit )
Shutdown non responding websocket connections in the client #326 ( commit )
Catch OSError exceptions from websockets package #328 ( commit )
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Skip CORS headers when origin is not given by client #131 ( commit )
Add async_handler s sub-package to setup.py ( commit )
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Address potential websocket cross-origin attacks #128 ( commit )
Documentation for the Same Origin security policy ( commit )
Remove tests from built package #124 ( commit ) (thanks Pablo Escodebar !)
Nothing published for this version
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Correctly autodetect asgi async mode #122 ( commit )
Omit response when asyncio websocket ends #120 ( commit )
Improved ocumentation on user session behavior on disconnections ( commit )
Correct spelling mistakes in documentation #119 ( commit ) (thanks Edward Betts !)
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Optimization to static file serving ( commit )
Do not reset connection when packet queue timeouts #110 ( commit ) (thanks Victor Moyano !)
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Much more flexible support for static files in the server ( commit , commit )
Correctly handle rejected websocket connections in Tornado #114 ( commit )
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Add JSONP support in the server #98 ( commit ) (thanks StoneMoe !)
Send binary packets as such in the sync client #112 ( commit )
Handle CLOSE packet in the client #100 ( commit )
Document how to access the sid for the connection ( commit )
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