FastAPI 0.139.0

Release Date: July 1, 2026

OK FASTAPI 0.139.0 JUST DROPPED ☕️

We're not even a month past 0.138 and Tiangolo is already back with another one period.

The headline feature? Dependencies in app.frontend(). That's right — you can now use dependency injection for your frontend routes just like your API routes period.

What does this mean for you:

Automatic cookie-based auth for your frontend? Done.
Session validation before your SPA loads? Easy.
User-specific frontend config without messy middleware? Yup.

This is a game-changer for anyone building full-stack FastAPI apps period.

Here's the gist: app.frontend(dependencies=[Depends(get_current_user)]) and boom — your HTML routes now have the same clean DI your API endpoints do.

No more copy-pasting auth logic between API and frontend routes period.

Also in this release: a ton of translation updates (12 languages refreshed). The docs are getting love too.

Is it a breaking change? Nope — 100% additive period.

Go update rn 🔗 pip install --upgrade fastapi

Full changelog on GitHub if you want the details period.

What is New?