JWT token propagation in Microservices - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JWT token propagation in microservices?

JWT token propagation means passing the user's JWT token from one microservice to another to maintain user identity and permissions across services.

beginner

Why is JWT token propagation important in microservices?

It allows each microservice to verify the user's identity and permissions without needing to ask the user to log in again, enabling secure and seamless communication.

intermediate

How is a JWT token typically propagated between microservices?

The JWT token is usually sent in the HTTP Authorization header as a Bearer token when one microservice calls another.

intermediate

What should a microservice do when it receives a JWT token?

It should validate the token's signature, check expiration, and verify claims to ensure the token is valid and the user is authorized.

advanced

Name one common challenge with JWT token propagation in microservices.

One challenge is token expiration and refresh, as tokens may expire during long chains of service calls, requiring strategies to refresh or reissue tokens.

Where is the JWT token usually sent when propagating between microservices?

A In the HTTP response body

B In the URL query parameters

C In the HTTP Authorization header as a Bearer token

D In a cookie only

JWT tokens are commonly sent in the Authorization header as Bearer tokens for security and standardization.

What must a microservice do before trusting a received JWT token?

A Ignore the token if it looks long

B Validate the token signature and claims

C Send the token back to the client

D Store the token in a database

Validating the token signature and claims ensures the token is authentic and not tampered with.

What problem can occur if JWT tokens expire during propagation?

A Tokens lose their signature

B Tokens become larger in size

C Tokens get automatically refreshed

D Services may reject requests due to invalid tokens

Expired tokens cause services to reject requests, so handling token refresh is important.

Which of these is NOT a typical claim in a JWT token?

A User password

B Expiration time

C User ID

D Issuer

Passwords should never be included in JWT claims for security reasons.

What is a common way to handle token propagation in asynchronous microservice calls?

A Include the JWT token in message headers or metadata

B Send the token in the request body only

C Do not propagate tokens in async calls

D Use cookies only

In async calls, tokens are often included in message headers or metadata to maintain identity.

Explain how JWT token propagation works in a microservices system and why it is necessary.

Think about how a user stays logged in when multiple services talk to each other.

Describe common challenges and best practices when implementing JWT token propagation.

Consider what can go wrong and how to keep tokens safe and valid.