Bearer Token vs API Key
Bearer Token (JWT)
Pros
- Self-contained claims — no DB lookup per request
- Short-lived with built-in expiry (exp claim)
- Supports fine-grained authorization via claims
- Standard Authorization: Bearer header format
Cons
- Larger than API keys
- Requires signature verification infrastructure
- Revocation needs blacklist or short TTL
- Overkill for simple service-to-service calls
API Key
Pros
- Simple opaque string — easy to implement
- Ideal for server-to-server and developer portals
- Easy to revoke by deleting from database
- Works without JWT libraries
Cons
- Long-lived by default — high impact if leaked
- No built-in expiry or claims
- Often sent as query param (bad practice)
- Requires server-side lookup on every request
Verdict
Use bearer tokens (typically JWTs) for user-facing authentication where claims, expiry, and stateless verification matter — mobile apps, SPAs, and microservice meshes. Use API keys for machine-to-machine access, developer integrations, and webhook authentication where simplicity wins. Never expose API keys in client-side code. Hash API keys before database storage and prefix them for identification. Many platforms use both: JWTs for user sessions and API keys for programmatic access.
Related Tools
Deeper Reading
Frequently Asked Questions
Can an API key be a JWT?
Technically yes, but API keys are usually opaque random strings stored server-side. JWTs are better when you need embedded claims.
Which is easier to rotate?
API keys — delete the old key and issue a new one. JWT rotation requires reissuing tokens or waiting for expiry.