"Should I use API keys or JWTs?" It's one of the most common questions when building an API. The honest answer: it depends. Both have their place, and the right choice depends on your use case.
In this guide, we'll break down the differences, when to use each, and when you might want both.
Quick Overview
| Aspect | API Keys | JWTs |
|---|---|---|
| Primary use | Service-to-service | User authentication |
| Contains data | ||
| Stateless validation | ||
| Easy revocation | ||
| Expiration | Optional/long | Required/short |
| Complexity | Simple | More complex |
What Are API Keys?
An API key is a unique identifier that authenticates requests to your API. It's typically a long, random string like:
hfy_live_a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6The server validates the key against a database to determine if the request is authorized and what permissions it has.
How API Keys Work
- Client includes API key in request header
- Server looks up key in database
- Server retrieves associated permissions, limits, and customer info
- Server processes request according to those rules
API Key Pros
- Simple to implement - Just a string comparison
- Easy to revoke - Delete from database, instantly invalid
- Good for rate limiting - Easy to track usage per key
- Long-lived - No refresh flow needed
- Developer-friendly - Copy, paste, done
API Key Cons
- Requires database lookup - Each request hits the database
- No built-in data - Key itself doesn't contain information
- Security if leaked - Long-lived keys are risky if exposed
What Are JWTs?
A JSON Web Token (JWT) is a self-contained token that encodes data and is cryptographically signed. The token contains three parts: header, payload, and signature. The payload contains "claims" - data about the user, their permissions, and when the token expires.
When to Use API Keys
API keys are the better choice for:
- Service-to-service authentication - Backend systems calling your API
- Developer platforms - Third-party developers integrating your API
- Rate limiting and billing - Track usage per customer/key
- Long-running integrations - Where refresh flows are impractical
- Simplicity - When you don't need JWT's features
When to Use JWTs
JWTs are the better choice for:
- User authentication - Login flows for end users
- Session management - Web/mobile app sessions
- Microservices - Passing user context between services
- Temporary access - Short-lived permissions
- Stateless systems - When you can't afford database lookups
Common Mistakes
1. Using JWTs as API Keys
Some teams use long-lived JWTs as API keys. This combines the worst of both: hard to revoke and complex without benefits.
2. Not Validating JWT Signatures
Always verify the signature. Never just decode and trust the payload.
3. Storing API Keys Insecurely
API keys should be treated like passwords. Don't log them, commit them, or expose them in URLs.
Can You Use Both?
Yes! Many systems use both:
- JWTs for user authentication (login, dashboard access)
- API keys for programmatic access (server-to-server, integrations)
This gives you the best of both worlds: secure user sessions and developer-friendly API access.
Summary
Use API Keys When
- • Service-to-service auth
- • Developer platforms
- • Rate limiting by customer
- • Long-lived access
- • Simplicity matters
Use JWTs When
- • User authentication
- • Session management
- • Microservices
- • Short-lived access
- • Need embedded claims
For most APIs serving developers and businesses, API keys are the right choice. They're simple, easy to manage, and integrate well with subscription billing.
API Key Management Made Easy
Holdify handles API key generation, verification, rate limiting, and subscription sync. Focus on your API, not key infrastructure.
Start FreeLast updated: January 9, 2026.