httpx httpx not playing along well with proxy with

The Fix

Upgrade to version 0.13.0 or later.

Based on closed encode/httpx issue #847 · PR/commit linked

Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.

Jump to Verify Open PR/Commit

@@ -176,7 +176,7 @@ client = httpx.Client(trust_env=False)
 ## HTTP Proxying
 
-HTTPX supports setting up proxies the same way that Requests does via the `proxies` parameter.
+HTTPX supports setting up HTTP proxies the same way that Requests does via the `proxies` parameter.
 For example to forward all HTTP traffic to `http://127.0.0.1:3080` and all HTTPS traffic

repro.py

proxy = httpx.Proxy(
        url=f"http://[username]%40[mail-domain]:[password]@{proxy}:80"
    )

    with httpx.Client(proxies=proxy, trust_env=False) as client:
        resp = client.get("https://www.gazzetta.it")
        print(resp.text)

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 0.13.0 or later.\nWhen NOT to use: Do not use this fix if the proxy does not require authentication.\n\n

Why This Fix Works in Production

Trigger: From reading the documentation of httpx it seems to me that the below should work but I am getting error code 407 which means that authentication definitely…
Mechanism: HTTPX did not create a Proxy-Authorization header for proxy URLs with credentials
Why the fix works: Detects credentials in proxy URLs and creates a Proxy-Authorization header, addressing issues with proxy authentication. (first fixed release: 0.13.0).

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

HTTPX did not create a Proxy-Authorization header for proxy URLs with credentials
Production symptom (often without a traceback): From reading the documentation of httpx it seems to me that the below should work but I am getting error code 407 which means that authentication definitely did not happen.

Proof / Evidence

GitHub issue: #847
Fix PR: https://github.com/encode/httpx/pull/780
First fixed release: 0.13.0
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.56

Discussion

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

Jump to Sources Open on GitHub

“Closing as a duplicate of https://github.com/encode/httpx/issues/779 for now, feel free to reopen if you come across any issues with the latest version of HTTPX. :)”

@florimondmanca · 2020-03-04 · confirmation · source

“Ah indeed, latest release is from Jan 17 (quite a while back now!), and #780 was merged on Jan 19”

@florimondmanca · 2020-03-04 · confirmation · source

“Cool! Time to sharpen up my pip voodoo. Thanks for the advice”

@AntonioL · 2020-03-04 · source

“Actually it seems similar to this issue: https://github.com/encode/httpx/pull/780 WIll try updating the httpx library.”

@AntonioL · 2020-03-04 · source

Failure Signature (Search String)

From reading the documentation of httpx it seems to me that the below should work but I am getting error code 407 which means that authentication definitely did not happen.
Closing as a duplicate of https://github.com/encode/httpx/issues/779 for now, feel free to reopen if you come across any issues with the latest version of HTTPX. :)

Copy-friendly signature

signature.txt

Failure Signature
-----------------
From reading the documentation of httpx it seems to me that the below should work but I am getting error code 407 which means that authentication definitely did not happen.
Closing as a duplicate of https://github.com/encode/httpx/issues/779 for now, feel free to reopen if you come across any issues with the latest version of HTTPX. :)

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
From reading the documentation of httpx it seems to me that the below should work but I am getting error code 407 which means that authentication definitely did not happen.
Closing as a duplicate of https://github.com/encode/httpx/issues/779 for now, feel free to reopen if you come across any issues with the latest version of HTTPX. :)

Minimal Reproduction

repro.py

proxy = httpx.Proxy(
        url=f"http://[username]%40[mail-domain]:[password]@{proxy}:80"
    )

    with httpx.Client(proxies=proxy, trust_env=False) as client:
        resp = client.get("https://www.gazzetta.it")
        print(resp.text)

What Broke

Users experienced authentication failures when using proxies requiring credentials.

Why It Broke

HTTPX did not create a Proxy-Authorization header for proxy URLs with credentials

Fix Options (Details)

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

Upgrade to version 0.13.0 or later.

When NOT to use: Do not use this fix if the proxy does not require authentication.

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/780

First fixed release: 0.13.0

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

When NOT to Use This Fix

Do not use this fix if the proxy does not require authentication.

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
0.13.0	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 httpx not playing along well with proxy with authentication (Fix)