Implementing JWT Authentication In a FastAPI Application

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In this blog post, we’ll walk through implementing JWT (JSON Web Token) authentication in a FastAPI application. JWTs are a compact, URL-safe means of representing claims between two parties, commonly used for secure authentication.

What is JWT?

JWT stands for JSON Web Token. It’s a standard for creating tokens that assert some number of claims. These tokens are signed with a secret key or a public/private key pair. Here’s a simple breakdown of how JWT works:

1. Header: Typically consists of two parts: the type of token (JWT) and the signing algorithm (e.g., HMAC SHA256 or RSA).

{
  "alg": "HS256",
  "typ": "JWT"
}

1. Payload: Claims are statements about an entity (typically, the user) and additional data.

{
  "username":"rajan",
  "email":"rajan12@rajan.com"
}

1. Signature: To create the signature part, you need to take the encoded header, the encoded payload, a secret, and the algorithm specified in the header, and sign that.

# secret id
ABjhjdsjfsh234fjhuih324$jihdfdshkgsog

Benefits of JWT: