Features

• ✨ Add support for streaming JSON Lines and binary data with yield. PR #15022 by @tiangolo.
  • This also upgrades Starlette from >=0.40.0 to >=0.46.0, as it's needed to properly unrwap and re-raise exceptions from exception groups.
  • New docs: Stream JSON Lines.
  • And new docs: Stream Data.

Docs

• 📝 Update Library Agent Skill with streaming responses. PR #15024 by @tiangolo.
• 📝 Update docs for responses and new stream with yield. PR #15023 by @tiangolo.
• 📝 Add await in StreamingResponse code example to allow cancellation. PR #14681 by @casperdcl.
• 📝 Rename docs_src/websockets to docs_src/websockets_ to avoid import errors. PR #14979 by @YuriiMotov.

Internal

• 🔨 Run tests with pytest-xdist and pytest-cov. PR #14992 by @YuriiMotov.

Features

• 🔧 Add FastAPI Agent Skill. PR #14982 by @tiangolo.
  • Read more about it in Library Agent Skills.

Internal

• ✅ Fix all tests are skipped on Windows. PR #14994 by @YuriiMotov.

Upgrades

• ⬆️ Add support for Starlette 1.0.0+. PR #14987 by @tiangolo.

Refactors

• ♻️ Refactor logic to handle OpenAPI and Swagger UI escaping data. PR #14986 by @tiangolo.

Internal

• 👥 Update FastAPI People - Experts. PR #14972 by @tiangolo.
• 👷 Allow skipping benchmark job in test workflow. PR #14974 by @YuriiMotov.

Breaking Changes

• 🔒️ Add strict_content_type checking for JSON requests. PR #14978 by @tiangolo.
  • Now FastAPI checks, by default, that JSON requests have a Content-Type header with a valid JSON value, like application/json, and rejects requests that don't.
  • If the clients for your app don't send a valid Content-Type header you can disable this with strict_content_type=False.
  • Check the new docs: Strict Content-Type Checking.

Internal

• ⬆ Bump flask from 3.1.2 to 3.1.3. PR #14949 by @dependabot[bot].
• ⬆ Update all dependencies to use griffelib instead of griffe. PR #14973 by @svlandeg.
• 🔨 Fix FastAPI People workflow. PR #14951 by @YuriiMotov.
• 👷 Do not run codspeed with coverage as it's not tracked. PR #14966 by @tiangolo.
• 👷 Do not include benchmark tests in coverage to speed up coverage processing. PR #14965 by @tiangolo.

Breaking Changes

• 🗑️ Deprecate ORJSONResponse and UJSONResponse. PR #14964 by @tiangolo.

Features

• ✨ Serialize JSON response with Pydantic (in Rust), when there's a Pydantic return type or response model. PR #14962 by @tiangolo.
  • This results in 2x (or more) performance increase for JSON responses.
  • New docs: Custom Response - JSON Performance.

Internal

• ⬆️ Upgrade pytest. PR #14959 by @tiangolo.
• 👷 Fix CI, do not attempt to publish fastapi-slim. PR #14958 by @tiangolo.
• ➖ Drop support for fastapi-slim, no more versions will be released, use only "fastapi[standard]" or fastapi. PR #14957 by @tiangolo.
• 🔧 Update pyproject.toml, remove unneeded lines. PR #14956 by @tiangolo.

Fixes

• ♻️ Fix JSON Schema for bytes, use "contentMediaType": "application/octet-stream" instead of "format": "binary". PR #14953 by @tiangolo.

Docs

• 🔨 Add Kapa.ai widget (AI chatbot). PR #14938 by @tiangolo.
• 🔥 Remove Python 3.9 specific files, no longer needed after updating translations. PR #14931 by @tiangolo.
• 📝 Update docs for JWT to prevent timing attacks. PR #14908 by @tiangolo.

Translations

• ✏️ Fix several typos in ru translations. PR #14934 by @argoarsiks.
• 🌐 Update translations for ko (update-all and add-missing). PR #14923 by @YuriiMotov.
• 🌐 Update translations for uk (add-missing). PR #14922 by @YuriiMotov.
• 🌐 Update translations for zh-hant (update-all and add-missing). PR #14921 by @YuriiMotov.
• 🌐 Update translations for fr (update-all and add-missing). PR #14920 by @YuriiMotov.
• 🌐 Update translations for de (update-all) . PR #14910 by @YuriiMotov.
• 🌐 Update translations for ja (update-all). PR #14916 by @YuriiMotov.
• 🌐 Update translations for pt (update-all). PR #14912 by @YuriiMotov.
• 🌐 Update translations for es (update-all and add-missing). PR #14911 by @YuriiMotov.
• 🌐 Update translations for zh (update-all). PR #14917 by @YuriiMotov.
• 🌐 Update translations for uk (update-all). PR #14914 by @YuriiMotov.
• 🌐 Update translations for tr (update-all). PR #14913 by @YuriiMotov.
• 🌐 Update translations for ru (update-outdated). PR #14909 by @YuriiMotov.

Internal

• 👷 Always run tests on push to master branch and when run by scheduler. PR #14940 by @YuriiMotov.
• 🎨 Upgrade typing syntax for Python 3.10. PR #14932 by @tiangolo.
• ⬆ Bump cryptography from 46.0.4 to 46.0.5. PR #14892 by @dependabot[bot].
• ⬆ Bump pillow from 12.1.0 to 12.1.1. PR #14899 by @dependabot[bot].

Breaking Changes

• ➖ Drop support for Python 3.9. PR #14897 by @tiangolo.

Refactors

• 🎨 Update internal types for Python 3.10. PR #14898 by @tiangolo.

Docs

• 📝 Update highlights in webhooks docs. PR #14905 by @tiangolo.
• 📝 Update source examples and docs from Python 3.9 to 3.10. PR #14900 by @tiangolo.

Internal

• 🔨 Update docs.py scripts to migrate Python 3.9 to Python 3.10. PR #14906 by @tiangolo.