FastAPI 0.138.1

Release Date: June 25, 2026

FastAPI 0.138.1 has been released as a maintenance update on June 25, 2026. This release focuses on internal refactoring, documentation improvements, and dependency upgrades to ensure continued stability and compatibility.

Overview

FastAPI 0.138.1 is a patch release that refactors the internal library skill system for better agent discoverability, simplifies the pull request workflow automation, and addresses several documentation quality issues. No breaking changes are introduced in this release.

Refactored Library Skills

The internal Library Skills system has been reworked to make information easier to find for AI coding agents and automated tooling. This change improves how the FastAPI codebase exposes its API surface to external developer tools and assistants, ensuring that agent-based workflows can more accurately interpret FastAPI's capabilities.

Workflow Improvements

Pull request trigger configurations have been simplified across the repository. This reduces friction for community contributors and streamlines the CI/CD pipeline. Additionally, enhanced workflow security checks have been added to maintain the integrity of the build process.

Documentation Fixes

Several grammar corrections, typographical fixes, and broken link repairs have been applied throughout the documentation. Release note pages now include proper date headers, and link handling has been improved to prevent stale references.

Dependency Updates

Upgraded Starlette supported version range to starlette>=0.40.0,<1.0.0 for forward compatibility
Pydantic dependency compatibility verified
Various test dependency bumps applied

Upgrade Notes

No breaking changes are present in this release. To upgrade, run:

pip install --upgrade fastapi