Introduction

*JSON Web Tokens (JWT)** are a type of token-based authentication used for securing web applications. They are compact and self-contained, making them a popular choice for secure communication between two parties. In this article, we’ll cover what JWT is, how it works, and when to use it.

What is JWT?

A JSON Web Token is a JSON object that is used to securely transmit information between parties. The information can be verified and trusted, because it is digitally signed. The token consists of three parts: header, payload, and signature.

The header typically consists of two parts: the type of the token, which is JWT, and the signing algorithm being used, such as HMAC SHA256 or RSA.

The payload contains the claims. Claims are statements about an entity (typically, the user) and additional metadata. There are three types of claims: registered, public, and private claims.

The signature is used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn’t changed along the way.

How JWT Works?

JWT authentication works by sending a token in the HTTP header with each request. When a user logs into an application, the server generates a token and returns it to the client. The client then sends the token with each subsequent request to the server. The server can then verify the token and determine whether the user is authenticated or not.

JWT authentication can be used with any method of sending data (such as POST, GET, and so on), but it is usually sent in the HTTP header as a Bearer Token.

When to use JWT?

JWT is a good choice for authentication in microservices and single-page applications. JWT can be used when both the client and the server are written in different languages and can be a good option for creating API authentication.

JWT is also stateless, meaning that the server does not need to store the user’s session information. This makes JWT a good choice for serverless applications or when scalability is a concern.

Conclusion

JWT is a popular option for token-based authentication in web applications. It is compact, self-contained, and stateless, making it a good choice for secure communication between two parties. When used correctly, JWT can provide a secure and scalable solution for authentication in your web application.