API Authentication with JWT — Tokens, Sessions & Security
How JWT authentication works for APIs. Access tokens, refresh tokens, and comparison with session cookies.
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JWT API Authentication
APIs need to know who is calling. JWTs are signed tokens containing user claims — stateless and popular for SPAs and mobile apps.
Why JWT authentication Matters
SPAs and mobile apps authenticate with tokens — JWT is the most common format you'll implement or debug.
Sign tokens server-side, verify on every protected route, use short expiry plus refresh tokens for long sessions.
JWT authentication — Key Ideas You Must Know
- Login returns signed JWT
- Client sends Authorization: Bearer token
- Server verifies signature
- Refresh tokens for long sessions
- HttpOnly cookies alternative for XSS safety
Practice JWT authentication with Free Lessons
Study auth patterns while building projects after JavaScript fundamentals on Sturdee.
Tip: Free interactive lesson: /tutorials/javascript — practice JWT authentication with runnable code on Sturdee.
API Authentication with JWT — FAQ
Frequently Asked Questions
JWT vs sessions?+
JWTs scale statelessly. Sessions are simpler and easier to revoke.
Continue learning interactively
Free tutorial: /tutorials/javascript →