# AN-2026-0801: Starlette 1.2 (May 28, 2026): TestClient prefers httpx2; with httpx it warns "Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead."

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- id: AN-2026-0801 (version 1; cite https://breakwire.org/claim/AN-2026-0801/v/1)
- kind: breaking · status: active · review: editor
- source: <https://github.com/Kludex/starlette/blob/1.10.0/starlette/testclient.py#L28-L45>
- more sources: <https://starlette.dev/release-notes/#:~:text=Support%20httpx2%20in%20the%20test%20client> <https://github.com/Kludex/starlette/blob/1.10.0/docs/release-notes.md#L187>
- event date: 2026-05-28
- services: starlette, fastapi, python
- affected: pypi:starlette >=1.2.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Starlette release notes (opened 2026-11-04): 1.2.0 (May 28, 2026) Support httpx2 in the test client (#3291); 1.2.1 uses httpx2 for type checking in the testclient module; 1.3.0 (June 11, 2026) adds httpx2 to the full extra and adjusts testclient typing and warnings.  [✓0 ✗0]
1. Starlette source (1.10.0 starlette/testclient.py; same warning in 1.2.0, 1.3.0, 1.4.0, 1.7.0 wheels checked on the box): imports httpx2 first; if only httpx is installed it warns StarletteDeprecationWarning "Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead."; if neither is installed it raises RuntimeError "The starlette.testclient module requires the httpx2 package to be installed."  [✓0 ✗0]
2. Reproduced 2026-11-04: importing fastapi.testclient with fastapi 0.162.0 / starlette 1.10.0 / httpx 0.28.1 emits the warning, which fails pytest runs configured with filterwarnings = error.  [✓0 ✗0]

## Fix
```text
Add `httpx2` to test dependencies (`pip install httpx2`, or `starlette[full]` >=1.3); keep `httpx` only if your own code imports it. Until then, filter the warning in pytest: `filterwarnings = ["ignore::starlette.exceptions.StarletteDeprecationWarning"]`.
```

## Error signatures
- substring: `Using 'httpx' with 'starlette.testclient' is deprecated; install 'httpx2' instead.` (starlette/testclient.py warnings.warn (1.10.0); reproduced)
- substring: `The starlette.testclient module requires the httpx2 package to be installed.` (starlette/testclient.py RuntimeError (1.10.0))

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (FastAPI release notes + 0.162.0 source, Starlette release notes + 1.10.0 source; messages reproduced on fastapi 0.162.0 / starlette 1.10.0)