FastAPI 0.141.0

FastAPI 0.141.0 has been released — a new feature release that introduces a convenient app.frontend() helper for local development workflows. Released on July 29, 2026.

New Feature: app.frontend()

The headline feature in FastAPI 0.141.0 is the addition of app.frontend(check_dir="auto"). When using fastapi dev for local development, this new method automatically detects and serves your frontend build directory, making it much more convenient to work on full-stack applications without needing to configure a separate static file server.

Here's how it works in practice:

from fastapi import FastAPI

app = FastAPI()

# Automatically detects the frontend build directory
app.frontend(check_dir="auto")

The check_dir="auto" mode scans common frontend output directories — such as dist, build, or .output — and serves the first one it finds. This eliminates the need for manual configuration in many projects and streamlines the development feedback loop.

This feature is particularly useful for:

• Developers using FastAPI with frontend frameworks like React, Vue, or Svelte
• Teams running FastAPI as a full-stack framework during development
• Rapid prototyping where you want to get a server running with minimal boilerplate

How to Upgrade

To upgrade to FastAPI 0.141.0, run:

pip install --upgrade fastapi

Or if you use Poetry:

poetry add fastapi@latest

This release is backwards compatible — no breaking changes or migration steps are required. All existing FastAPI applications will continue to work as before.