Difference Between Access Token and Refresh Token

Access tokens and refresh tokens are both part of token-based authentication in modern web applications, especially when using OAuth or JWT-based (JSON Web Token) systems. Here’s a breakdown of each:

Access Token

• Purpose: The access token is a short-lived token used to authorize and grant access to a user’s session or resource.

• Lifetime: Access tokens typically have a shorter lifespan (often 15 minutes to a few hours) to minimize the security risk if compromised.

• Usage: Once a user logs in, the server issues an access token, which is sent in each request to authenticate the user. This token is usually included in an HTTP header, often as Authorization: Bearer <token>.

• Security: Because of its short lifespan, access tokens provide better security against attacks, as the token expires quickly if it is intercepted by an attacker.

Refresh Token

• Purpose: The refresh token is used to obtain a new access token when the current one expires. It allows the user to stay logged in without needing to re-enter credentials.

• Lifetime: Refresh tokens have a much longer lifespan than access tokens, sometimes days or months, allowing users to continue accessing the application.

• Usage: When the access token expires, the client (often a frontend app) sends the refresh token to the server. The server then verifies it and issues a new access token.

• Security: Refresh tokens are often stored securely (e.g., in a secure HTTP-only cookie) and are typically used server-side only. If a refresh token is compromised, an attacker can request new access tokens, so extra precautions, such as storing it securely and monitoring for abuse, are necessary.

Key Differences

For a more visual explanation, check out this video on access tokens and refresh tokens.

Using both access and refresh tokens enables secure, long-lived sessions with limited exposure to security risks, balancing security and usability for the user.