Next.js
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JWT Authentication
Definition
JSON Web Tokens: A stateless authentication mechanism where the user's identity data is cryptographically signed and stored directly inside the token itself.
Explain Like I'm New
Instead of the server storing a list of who is logged in, the server gives the user a mathematically sealed 'badge' containing their User ID. Every time the user makes a request, they show the badge. The server checks the math signature. If the signature is valid, the server trusts the badge.
Real World Example
Microservice architectures. An Auth server issues the JWT. The user takes that JWT and uses it to access the Billing server. The Billing server doesn't need to talk to the Auth server; it just mathematically verifies the JWT's signature.
Common Use Cases
- •Stateless APIs
- •Mobile app authentication
- •Microservices
Interactive Example
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Interview Questions
basic
- What does JWT stand for?
intermediate
- Why is it dangerous to put sensitive information like a Social Security Number inside a JWT payload?