JSON Web Token (JWT) has become one of the most popular authorization mechanisms in web applications and APIs. However, its popularity often leads to JWT being used in scenarios where it is not the best choice.

In this article, we analyze the advantages, disadvantages, and alternatives to JWT.

What Is JWT?

JWT is a stateless token containing a set of claims, cryptographically signed. This allows the backend to verify its validity without storing session state.

Advantages of JWT

Scalability

JWT works very well in distributed systems because it does not require centralized session storage.

Ease of Integration

The token can be sent in an HTTP header, making integration with frontend and mobile applications straightforward.

No Dependency on Storage

The backend does not need to query a database on every request.

Disadvantages of JWT

Difficult Revocation

JWT remains valid until it expires. Revoking a token requires additional mechanisms such as blacklists.

Browser Storage Risks

Storing JWT in localStorage increases exposure to XSS attacks.

Token Size Overhead

A large number of claims increases token size and network overhead.

Alternatives to JWT

Traditional Sessions

A proven solution, easy to revoke and secure when used with HttpOnly cookies.

Opaque Tokens

Tokens with no semantic meaning that require server-side validation.

OAuth 2.0

A better choice for systems with multiple clients and external integrations.

Summary

JWT is a powerful tool, but not a universal solution. A conscious choice of authorization mechanism is crucial for system security and stability.