What is an API Key?
An API key is a unique alphanumeric string that identifies and authenticates an application or user making requests to an API (Application Programming Interface). It serves as a simple credential that allows API providers to track usage, enforce rate limits, and control access to their services.
How API Keys Work
- Developer registers with the API provider
- Provider generates a unique API key
- Developer includes the key in API requests
- Provider validates the key and processes the request
Security Best Practices
- Never expose API keys in client-side code
- Store keys in environment variables or secrets managers
- Rotate keys regularly
- Use different keys for development and production
- Implement key scoping and permissions
- Monitor for unauthorized usage
API Keys vs. Other Auth Methods
| Method | Use Case | Security Level |
|---|---|---|
| API Key | Simple authentication | Basic |
| OAuth 2.0 | User authorization | High |
| JWT | Stateless auth | Medium-High |
| mTLS | Service-to-service | Very High |