httpx Can't handle URLs with @ character in userinfo

The Fix

Upgrade to version 0.14.2 or later.

Based on closed encode/httpx issue #328 · 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%.

Jump to Verify Open PR/Commit

@@ -7,7 +7,7 @@
 from collections.abc import MutableMapping
 from http.cookiejar import Cookie, CookieJar
-from urllib.parse import parse_qsl, urlencode
+from urllib.parse import parse_qsl, quote, unquote, urlencode

repro.py

>> import httpx
>> httpx.URL("https://[email protected]:[email protected]")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sethmlarson/Desktop/http3/httpx/models.py", line 112, in __init__
    raise InvalidURL("No host included in URL.")
httpx.exceptions.InvalidURL: No host included in URL.

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.14.2 or later.\nWhen NOT to use: This fix should not be applied if the URL parsing behavior needs to remain unchanged.\n\n

Why This Fix Works in Production

Trigger: >> import httpx
Mechanism: The URL parser fails to handle special characters like '@' in the userinfo section
Why the fix works: Handles URL quoting for username and password components, allowing for proper parsing of URLs with special characters like '@'. (first fixed release: 0.14.2).

Production impact:

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

The URL parser fails to handle special characters like '@' in the userinfo section
Surfaces as: >> import httpx

Proof / Evidence

GitHub issue: #328
Fix PR: https://github.com/encode/httpx/pull/1159
First fixed release: 0.14.2
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).

Jump to Sources Open on GitHub

“Hi @sethmlarson I've pushed a PR about this topic. Could your review it?”

@cansarigol · 2019-09-09 · source

“So, something I think we may want to re-review prior to 1.0 is which internal URL parsing implementation is really our best option”

@lovelydinosaur · 2020-07-27 · confirmation · source

Failure Signature (Search String)

>> import httpx

Error Message

Stack trace

error.txt

Error Message
-------------
>> import httpx
>> httpx.URL("https://[email protected]:[email protected]")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sethmlarson/Desktop/http3/httpx/models.py", line 112, in __init__
    raise InvalidURL("No host included in URL.")
httpx.exceptions.InvalidURL: No host included in URL.

Minimal Reproduction

repro.py

>> import httpx
>> httpx.URL("https://[email protected]:[email protected]")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sethmlarson/Desktop/http3/httpx/models.py", line 112, in __init__
    raise InvalidURL("No host included in URL.")
httpx.exceptions.InvalidURL: No host included in URL.

What Broke

Users encounter an InvalidURL exception when using email addresses as usernames.

Why It Broke

The URL parser fails to handle special characters like '@' in the userinfo section

Fix Options (Details)

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

Upgrade to version 0.14.2 or later.

When NOT to use: This fix should not be applied if the URL parsing behavior needs to remain unchanged.

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/1159

First fixed release: 0.14.2

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

When NOT to Use This Fix

This fix should not be applied if the URL parsing behavior needs to remain unchanged.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

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
0.14.2	Fixed

Related Issues

No related fixes found.

Cluster: httpx:configuration-error All hubs All clusters

Related clusters: Data consistency Other Timeout

Sources

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

httpx Can't handle URLs with @ character in userinfo section (Fix)