**FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request`.

## Override the default exception handlers

**FastAPI** has some default exception handlers.

!!! note "Technical Details"
    You could also use `from starlette.templating import Jinja2Templates`.

    **FastAPI** provides the same `starlette.templating` as `fastapi.templating` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request` and `StaticFiles`.

## Writing templates

Then you can write a template at `templates/item.html` with, for example:

```jinja hl_lines="7"

## Automatic conversion

`Header` has a little extra functionality on top of what `Path`, `Query` and `Cookie` provide.

Most of the standard headers are separated by a "hyphen" character, also known as the "minus symbol" (`-`).

But a variable like `user-agent` is invalid in Python.

# Tutorial - User Guide

This tutorial shows you how to use **FastAPI** with most of its features, step by step.

Each section gradually builds on the previous ones, but it's structured to separate topics, so that you can go directly to any specific one to solve your specific API needs.

It is also built to work as a future reference.

So you can come back and see exactly what you need.

## Run the code

  conçu pour Django Channels.

## Machine serveur et programme serveur

Il y a un petit détail sur les noms à garder à l'esprit. 💡

Le mot "**serveur**" est couramment utilisé pour désigner à la fois l'ordinateur distant/cloud (la machine physique ou virtuelle) et également le programme qui s'exécute sur cette machine (par exemple, Uvicorn).

And as you would be building the container image again and again during development to check that your code changes are working, there's a lot of accumulated time this would save.

!!! note
    Notice that most of the code is the standard `SQLAlchemy` code you would use with any framework.

    The **FastAPI** specific code is as small as always.

## ORMs

# Settings and Environment Variables

In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

## Environment Variables

!!! tip

!!! note "Technical Details"
    You could also use `from starlette.responses import JSONResponse`.

    **FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `status`.

## OpenAPI and API docs

!!! tip
    Integrating other authentication/authorization providers like Google, Facebook, Twitter, GitHub, etc. is also possible and relatively easy.

    The most complex problem is building an authentication/authorization provider like those, but **FastAPI** gives you the tools to do it easily, while doing the heavy lifting for you.

## **FastAPI** utilities