bare websockets

[benedikt-bartscher]

saves ~11.6 KB gz / ~41 KB raw frontend size (a small js chunk replaces whole socketio)
dropped python deps: wsproto, simple-websocket, python-socketio, python-engineio, bidict
new benchmarks in test_event_transport.py show about 2x performance increase compared to socketio

also migrates AppHarness to granian for consistency. otherwise downstream tests using AppHarness still need uvicorn and wsproto/websockets

[codspeed-hq]

Merging this PR will not alter performance

✅ 32 untouched benchmarks
🆕 4 new benchmarks
⏩ 8 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
🆕	test_transport_inbound_socketio	N/A	7.9 ms	N/A
🆕	test_transport_inbound_websocket	N/A	4.4 ms	N/A
🆕	test_transport_outbound_socketio	N/A	15.4 ms	N/A
🆕	test_transport_outbound_websocket	N/A	6.7 ms	N/A

---

_{Comparing benedikt-bartscher:make-sio-optional (1120e0e) with main (8853e14)}

Footnotes

1. 8 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[greptile-apps]

Greptile Summary

The PR replaces the default Socket.IO transport with a lightweight plain-WebSocket protocol, retains Socket.IO as an optional transport, and migrates test serving to Granian.

• Adds the browser WebSocket client, handshake, heartbeat, reconnect, and event framing logic.
• Adds the corresponding ASGI event namespace and transport selection.
• Updates optional dependencies, server launch paths, AppHarness, tests, and benchmarks.

Confidence Score: 3/5

The PR does not yet appear safe to merge because linked clients can still generate unrestricted version-mismatch warnings through repeated reconnects.

The current connection path logs every linked version mismatch without applying the shared process-wide logging budget, leaving the previously reported backend log-exhaustion path outstanding.

Files Needing Attention: reflex/event_namespace.py

Important Files Changed

Filename	Overview
reflex/event_namespace.py	Implements the plain-WebSocket backend protocol and closes malformed event frames, but the previously reported version-mismatch warning remains outside the shared logging budget.
packages/reflex-base/src/reflex_base/.templates/web/utils/helpers/websocket.js	Implements the lightweight browser transport, with the previously requested human-readable timeout and unit documentation now present.
packages/reflex-base/src/reflex_base/.templates/web/utils/state.js	Selects the plain or optional Socket.IO transport and adds lifecycle cleanup for asynchronous connection setup.
reflex/utils/exec.py	Updates backend launch paths for Granian and optional Uvicorn WebSocket serving.
reflex/testing.py	Migrates AppHarness to an embedded Granian server and updates readiness and cleanup behavior.
pyproject.toml	Moves Socket.IO and Uvicorn-related dependencies into optional extras for the new default transport.
tests/units/test_event_namespace.py	Exercises connection validation, malformed-frame closure, UTF-8 byte limits, heartbeat behavior, and event dispatch.

_{Reviews (31): Last reviewed commit: "only warn about version mismatch for lin..." | Re-trigger Greptile}

[cubic-dev-ai]

All reported issues were addressed across 19 files

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All reported issues were addressed across 17 files

<sub>Requires human review: Auto-approval blocked because this review re-detected 1 unresolved issue already reported by Cubic.

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All reported issues were addressed across 4 files (changes from recent commits).

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[cubic-dev-ai]

All reported issues were addressed across 4 files (changes from recent commits).

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[cubic-dev-ai]

All reported issues were addressed across 6 files (changes from recent commits).

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[cubic-dev-ai]

All reported issues were addressed across 6 files (changes from recent commits).

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All reported issues were addressed across 1 file (changes from recent commits).

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All reported issues were addressed across 2 files (changes from recent commits).

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[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

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[abulvenz]

I really like this lightweight approach 👍 .
One thing that is dropped, correct me if I see this wrong: under the hood socketio supports HTTP long-polling in case a websocket connection cannot be established (e.g. due to badly configured load balancers, reverse proxies or simply disabled client support). In most cases that should be fixed anyways on server side for performance reasons.

[benedikt-bartscher]

I really like this lightweight approach 👍 . One thing that is dropped, correct me if I see this wrong: under the hood socketio supports HTTP long-polling in case a websocket connection cannot be established (e.g. due to badly configured load balancers, reverse proxies or simply disabled client support). In most cases that should be fixed anyways on server side for performance reasons.

Thanks 🙏

Yes, the new bare websockets implementation does not support http long-polling yet. However one could still choose the old socketio based transport to archive this. Also iirc longpolling was disabled by default anyway, i guess not a lot of users use it. If this is really needed i could add support to our bare websockets implementation as well.

[benedikt-bartscher]

check out #6984

edit: done in 9caa24b