What Is an API and API Key?

An API lets software talk to other software, and an API key identifies which account is making the request.

An API is a structured way for one software system to use another system. An API key is a secret credential that proves which account, app, or user is allowed to make requests.

In practice

For AI tools, an API key often controls model access, billing, rate limits, and permissions. A website or app sends prompts to an AI API and receives model responses in return.

What to watch

Treat API keys like passwords. Do not publish them in code, screenshots, browser consoles, public chats, or shared documents.