API Authentication Explained
API authentication explained: API keys, JWTs, OAuth 2.0 client credentials and token refresh, with live requests you can run against our sandbox.
Track 3 of 9 in API 101, our free API testing course for beginners.
- For Developers
- For QA and engineering leaders
API Keys: The Simplest Authentication That Still Trips People Up
Simple, common, and surprisingly easy to get wrong. Here's the API key playbook.
What Is a JWT? JSON Web Token Structure & Claims
A JWT packs identity claims into a signed string. Here's what's inside the header, payload and signature, and how a server decides to trust it.
OAuth 2.0 Client Credentials: Machine-to-Machine Auth Done Right
OAuth 2.0's machine-to-machine flow. Clean, standard, and easy to test once you see the shape.
Token Refresh Patterns: Rotating, Sliding, and Reactive Refresh
Short-lived access tokens need graceful refresh. Three common patterns, one big pitfall.
Practice these lessons on your own APIs.
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