Securing your API starts with choosing the right authentication method. Each approach serves different use cases—understanding these differences helps you protect your resources correctly.
API Keys for Simple Integrations
API keys are straightforward to implement and manage. A unique key identifies each consumer. Keys work well for server-to-server communication where you control both systems. They are simple to revoke and rotate. However, they offer no built-in expiration, scoped permissions, or user context.
JWT for Stateless Authentication
JSON Web Tokens contain claims that can be cryptographically verified without querying a database. A valid JWT proves the user’s identity and permissions at the moment of the request. JWTs work excellently in microservices architectures where you need stateless authorization across multiple services.
OAuth 2.0 for Delegated Access
OAuth 2.0 is the standard when third parties need user-authorized access. Instead of sharing credentials, users grant specific permissions to applications. The authorization code flow with PKCE is the recommended approach for most applications. OAuth handles token refresh, scoped access, and user consent correctly.
Matching Method to Use Case
Use API keys when you control both client and server and need simple identification. Use JWTs when you need fast, stateless authentication within your ecosystem. Use OAuth 2.0 when external applications need access on behalf of users, or when you need granular permission scopes.
Security Best Practices Apply to All
Always use HTTPS—never send credentials over plain HTTP. Rotate keys regularly. Implement key scoped limitations—don’t give every key full access. Log authentication failures. Never expose credentials in client-side JavaScript or mobile apps where attackers can extract them.