JWT

JWT (JSON Web Token) is a token format commonly used to maintain authenticated sessions in APIs.

After a user successfully authenticates, the server can generate a JWT containing information about the user. This token can then be used for authenticated API requests.

Code

import jwt

SECRET_KEY = "my-secret-key"

payload = {
    "user_id": 1
}

token = jwt.encode(
    payload,
    SECRET_KEY,
    algorithm="HS256"
)

print(token)

Understanding the Code

1. Import JWT

First, import the JWT library:

import jwt

2. Define the Secret Key

A secret key is used to sign the token:

SECRET_KEY = "my-secret-key"

The secret key should be kept secure in a real application.

3. Create the Payload

The payload contains information that will be stored in the token:

payload = {
    "user_id": 1
}

In this example, the payload contains the user’s ID.

4. Generate the Token

Use jwt.encode() to create the JWT:

token = jwt.encode(
    payload,
    SECRET_KEY,
    algorithm="HS256"
)

The token is created using:

• The payload
• The secret key
• The HS256 signing algorithm

5. Print the Token

print(token)

This displays the generated JWT.

Output

The generated token will look similar to:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...

JWT Flow

A basic JWT authentication flow looks like:

User Login
    ↓
Verify Credentials
    ↓
Create JWT
    ↓
Return Token
    ↓
Client Uses Token
    ↓
Authenticated API Requests

Summary

JWT provides a token-based way to maintain authenticated sessions in APIs.

The basic process is:

payload = {
    "user_id": 1
}

token = jwt.encode(
    payload,
    SECRET_KEY,
    algorithm="HS256"
)