---
description: The act of identifying oneself to the system.
---

# Authentication

Now we can delve into the core of this module. To have authentication, we'll use the **Passport** library. Nest offers integration with it, which makes our lives easier. The **Local** strategy will be used for the user to log in with credentials, and the **JWT** strategy, for him to identify himself to the routes after the previous step. Don't worry, everything will become clearer as the module progresses.

The first step is to install all the necessary dependencies.

```sh
yarn add @nestjs/passport passport passport-local @nestjs/jwt passport-jwt
yarn add -D @types/passport-local @types/passport-jwt
```

Then, let's begin by allowing the user to **log in**.
