The Fix
Upgrade to version 0.15.0 or later.
Based on closed Kludex/uvicorn issue #245 · PR/commit linked
Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.
@@ -51,6 +51,8 @@ Options:
--ws-max-size INTEGER WebSocket max size message in bytes
[default: 16777216]
+ --ws-ping-interval FLOAT WebSocket ping interval [default: 20.0]
+ --ws-ping-timeout FLOAT WebSocket ping timeout [default: 20.0]
--lifespan [auto|on|off] Lifespan implementation. [default: auto]
Option A — Upgrade to fixed release\nUpgrade to version 0.15.0 or later.\nWhen NOT to use: This fix is not suitable for non-WebSocket implementations.\n\n
Why This Fix Works in Production
- Trigger: Add ping-interval and ping-timeout options
- Mechanism: Uvicorn lacked configurable options for WebSocket ping interval and timeout
- Why the fix works: Adds options to set the WebSocket ping interval and timeout, allowing for better connection management. (first fixed release: 0.15.0).
- If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.
Why This Breaks in Prod
- Uvicorn lacked configurable options for WebSocket ping interval and timeout
- Production symptom (often without a traceback): Add ping-interval and ping-timeout options
Proof / Evidence
- GitHub issue: #245
- Fix PR: https://github.com/kludex/uvicorn/pull/1048
- First fixed release: 0.15.0
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.85
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.55
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“What's more, websockets have ping_intrval and ping_timeout parameter, which used to specify ping/pong circle interval. However, it seems uvicorn can only adapt the default values(which…”
“Any updates or other PRs on this yet? I think I can do it..”
Failure Signature (Search String)
- Add ping-interval and ping-timeout options
- What's more, websockets have ping_intrval and ping_timeout parameter, which used to specify ping/pong circle interval. However, it seems uvicorn can only adapt the default
Copy-friendly signature
Failure Signature
-----------------
Add ping-interval and ping-timeout options
What's more, websockets have ping_intrval and ping_timeout parameter, which used to specify ping/pong circle interval. However, it seems uvicorn can only adapt the default values(which are 20s both) and there is not way to specify them.
Error Message
Signature-only (no traceback captured)
Error Message
-------------
Add ping-interval and ping-timeout options
What's more, websockets have ping_intrval and ping_timeout parameter, which used to specify ping/pong circle interval. However, it seems uvicorn can only adapt the default values(which are 20s both) and there is not way to specify them.
Why It Broke
Uvicorn lacked configurable options for WebSocket ping interval and timeout
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
Upgrade to version 0.15.0 or later.
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/kludex/uvicorn/pull/1048
First fixed release: 0.15.0
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix is not suitable for non-WebSocket implementations.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Make timeouts explicit and test them (unit + integration) to avoid silent behavior changes.
- Instrument retries (attempt count + reason) and alert on spikes to catch dependency slowdowns.
Version Compatibility Table
| Version | Status |
|---|---|
| 0.15.0 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.