gg2
OpenAI migrates to HTTPX2
Archived — this story has rotated out of today’s deck. It is kept here in full.
The gist
OpenAI's Python SDK now uses HTTPX2 instead of httpx, changing TLS trust stores. Developers must update custom HTTP clients and certificate handling.
Background
OpenAI's Python SDK has migrated to HTTPX2, a new HTTP client library, replacing the previous httpx package. This change affects how applications interact with the SDK's HTTP layer, particularly around TLS certificate verification and custom client configurations. The migration is part of a broader industry shift, as Anthropic's Python library also switched to HTTPX2 in its v1.0.0 release.
How it unfolded
- recentlyOpenAI released v3.0.0 of its Python SDK, switching from httpx to HTTPX2. The SDK now installs HTTPX2 automatically and no longer installs httpx.
- Aug 22, 2026LLM changelog notes dropped support for Python 3.7 and other updates, but does not mention HTTPX2 directly.
- Aug 24, 2026Simon Willison's blog post about llm-anthropic 0.27 mentions that Anthropic's Python library also switched to HTTPX2, following OpenAI's change.
- Aug 25, 2026A blog post by Blake Crosley details the Anthropic Python SDK 1.0 migration, noting that response and error objects are now HTTPX2 types, and provides guidance on updating imports and isinstance checks.
Who’s saying what
- Official
- OpenAI's migration guide states that existing API calls, streaming, authentication, retries, and timeouts continue to work with the default HTTP client, but custom clients must use HTTPX2 objects.
- Expert
- Simon Willison notes that the change is significant for developers who relied on httpx being installed transitively, and recommends adding an explicit httpx dependency if needed.
- Caution
- Blake Crosley warns that isinstance checks and type annotations naming httpx.Response or httpx.Request will fail silently unless updated to httpx2, potentially causing bugs.