Token refresh mechanism in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a token refresh mechanism in REST APIs?

It is a process that allows clients to get a new access token using a refresh token when the original access token expires, without asking the user to log in again.

beginner

Why do REST APIs use refresh tokens instead of long-lived access tokens?

Because short-lived access tokens reduce security risks if stolen, and refresh tokens allow clients to get new access tokens securely without bothering the user frequently.

intermediate

What is the typical flow of a token refresh mechanism?

1. Client sends refresh token to the API's token endpoint.<br>2. Server verifies the refresh token.<br>3. Server issues a new access token (and sometimes a new refresh token).<br>4. Client uses the new access token for API calls.

beginner

What happens if a refresh token is expired or invalid?

The server rejects the refresh request, and the client must ask the user to log in again to get new tokens.

intermediate

How can you improve security when implementing token refresh mechanisms?

Use HTTPS to protect tokens in transit, store refresh tokens securely (e.g., HttpOnly cookies), limit refresh token lifespan, and detect suspicious refresh attempts.

What is the main purpose of a refresh token in REST APIs?

A To encrypt API requests

B To authenticate the user initially

C To get a new access token without user login

D To store user profile data

Refresh tokens allow clients to obtain new access tokens without requiring the user to log in again.

Which token usually has a shorter lifespan?

A Access token

B Refresh token

C Both have the same lifespan

D Neither expires

Access tokens are short-lived to reduce security risks, while refresh tokens last longer.

What should a client do if the refresh token is rejected by the server?

A Send the refresh token to another API

B Request a new access token using the old refresh token

C Ignore and continue using the expired access token

D Ask the user to log in again

If the refresh token is invalid or expired, the client must ask the user to log in again.

Where should refresh tokens be stored on the client side for better security?

A HttpOnly cookies

B Session storage

C Local storage

D In the URL

HttpOnly cookies prevent JavaScript access, reducing risk of token theft.

Which protocol is essential to secure token refresh requests?

A HTTP

B HTTPS

C FTP

D SMTP

HTTPS encrypts data in transit, protecting tokens from interception.

Explain the token refresh mechanism and why it is important in REST APIs.

Think about how users stay logged in without entering credentials repeatedly.

Describe the steps a client and server take during a token refresh request.

Imagine the client asking the server politely for a new key to keep accessing resources.