::: fastapi.security.APIKeyHeader

::: fastapi.security.APIKeyQuery

## HTTP Authentication Schemes

::: fastapi.security.HTTPBasic

::: fastapi.security.HTTPBearer

::: fastapi.security.HTTPDigest

## HTTP Credentials

::: fastapi.security.HTTPAuthorizationCredentials

::: fastapi.security.HTTPBasicCredentials

## OAuth2 Authentication

::: fastapi.security.OAuth2

    * Einem Cookie.
* `http`: Standard-HTTP-Authentifizierungssysteme, einschließlich:
    * `bearer`: ein Header `Authorization` mit dem Wert `Bearer` plus einem Token. Dies wird von OAuth2 geerbt.
    * HTTP Basic Authentication.
    * HTTP Digest, usw.
* `oauth2`: Alle OAuth2-Methoden zum Umgang mit Sicherheit (genannt „Flows“).

* A very powerful and easy to use **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.
* Security and authentication, including support for **OAuth2** with **JWT tokens** and **HTTP Basic** auth.
* More advanced (but equally easy) techniques for declaring **deeply nested JSON models** (thanks to Pydantic).

This is very useful when you need to:

* Have shared logic (the same code logic again and again).
* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.