What is an API Key?

What is an API Key?

An API key is a secret string that identifies the calling application when it accesses an API. The provider issues the key, and the client sends it with every request - usually in an Authorization header or a query parameter.

Why Use an API Key?

API keys let the provider track usage, enforce rate limits, apply billing, and revoke abusive clients. They are the simplest form of API authentication.

How to Keep It Safe

Treat an API key like a password. Store it in an environment variable or a secrets manager, never in source control or client-side code. Rotate keys regularly and revoke any key that may have leaked. Scope each key to the minimum permissions your application needs.