Rotating Refresh Tokens: A Smarter Way to Keep Your Users Secure

Rotating Refresh Tokens: A Smarter Way to Keep Your Users Secure
Aswanth Alakkadan
February 28, 2025
5 min read

Introduction

Authentication is the backbone of any modern web application. When users log in, they receive an access token that grants them permission to interact with the system. However, access tokens expire quickly to enhance security. This is where refresh tokens come into play—they allow users to get a new access token without having to log in again. But what happens if a refresh token gets stolen? This is where rotating refresh tokens step in.

What is a Refresh Token?

A refresh token is a long-lived token issued alongside the access token. Instead of prompting users to log in again when the access token expires, the refresh token is used to get a new one.

The Problem with Static Refresh Tokens

Traditional (static) refresh tokens remain the same throughout their lifespan. If an attacker steals it, they can generate new access tokens indefinitely—leading to a security risk.

What is a Rotating Refresh Token?

A rotating refresh token is a security mechanism where a new refresh token is issued each time a new access token is requested. The old refresh token is invalidated immediately, ensuring that stolen tokens cannot be reused.

How It Works

  1. User Logs In: The authentication server provides an access token (short-lived) and a refresh token (longer-lived).
  2. Access Token Expires: The client requests a new access token using the refresh token.
  3. New Refresh Token Issued: The server provides a fresh access token and a new refresh token while invalidating the old one.
  4. Repeat the Process: Each time an access token is refreshed, a new refresh token is issued.

Benefits of Rotating Refresh Tokens

  • Prevents Token Theft Abuse: If an attacker steals a refresh token, it becomes useless once rotated.
  • Better Session Management: If an old refresh token is used again, the server can detect a potential attack.
  • Enhances Security: It forces regular token updates, making it harder for attackers to hijack a session.

Implementing Rotating Refresh Tokens

Most modern authentication services, such as Auth0, Firebase, and OAuth 2.0-based systems, support rotating refresh tokens.

If you are building your own authentication system in a MERN (MongoDB, Express, React, Node.js) stack, you can implement rotating refresh tokens like this:

  1. Store refresh tokens securely in a database.
  2. Invalidate old refresh tokens upon issuing a new one.
  3. Detect anomalies if a refresh token is used multiple times.

Final Thoughts

Rotating refresh tokens add an extra layer of security to your authentication flow. By making refresh tokens short-lived and replacing them with each request, you significantly reduce the risk of token theft and session hijacking.

If you're building a web app with user authentication, consider implementing rotating refresh tokens to keep your users safe and secure!