httpx Renaming PoolLimits -> Limits. (Fix)

The Fix

Upgrade to version 0.14.0 or later.

Based on closed encode/httpx issue #1094 · PR/commit linked

Open PR/Commit

@@ -401,8 +401,8 @@ response = client.get('http://example.com/')
 ## Pool limit configuration
 
-You can control the connection pool size using the `pool_limits` keyword
-argument on the client. It takes instances of `httpx.PoolLimits` which define:
+You can control the connection pool size using the `limits` keyword

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.14.0 or later.\nWhen NOT to use: Do not use this fix if you require the old PoolLimits functionality.\n\n

Why This Fix Works in Production

Trigger: * `max_response_size = 100_000_000` # Raise an error on any responses >100MB.
Mechanism: Renamed PoolLimits to Limits to allow for broader limit configurations
Why the fix works: Renamed PoolLimits to Limits with gentle deprecation. (first fixed release: 0.14.0).

Why This Breaks in Prod

Renamed PoolLimits to Limits to allow for broader limit configurations
Production symptom (often without a traceback): * `max_response_size = 100_000_000` # Raise an error on any responses >100MB.

Proof / Evidence

GitHub issue: #1094
Fix PR: https://github.com/encode/httpx/pull/1113
First fixed release: 0.14.0
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.62

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“Some other thoughts around why this be a good renaming too”

@lovelydinosaur · 2020-07-30 · source

Failure Signature (Search String)

* `max_response_size = 100_000_000` # Raise an error on any responses >100MB.
* `max_request_duration = 60.0` # Raise an error on responses that exceed 1 minute total download time.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
* `max_response_size = 100_000_000`  # Raise an error on any responses >100MB.
* `max_request_duration = 60.0`  # Raise an error on responses that exceed 1 minute total download time.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
* `max_response_size = 100_000_000`  # Raise an error on any responses >100MB.
* `max_request_duration = 60.0`  # Raise an error on responses that exceed 1 minute total download time.

What Broke

Potential confusion and errors due to deprecated PoolLimits usage.

Why It Broke

Renamed PoolLimits to Limits to allow for broader limit configurations

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

Upgrade to version 0.14.0 or later.

When NOT to use: Do not use this fix if you require the old PoolLimits functionality.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/encode/httpx/pull/1113

First fixed release: 0.14.0

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

Do not use this fix if you require the old PoolLimits functionality.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
Upgrade behind a canary and run integration tests against the canary before 100% rollout.

Version Compatibility Table

Version	Status
0.14.0	Fixed

Related Issues

No related fixes found.

Cluster: httpx:other All hubs All clusters

Related clusters: Configuration error Data consistency Timeout

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.