API

An API (Application Programming Interface) is a set of rules and endpoints that lets two software systems communicate and exchange data securely. APIs are the messengers that let apps talk to each other.

How it works

1. 1Client request: the client (app) sends a request to the API.
2. 2API endpoint: the request hits the API endpoint.
3. 3Authentication: the API verifies the key, token and permissions.
4. 4Process request: the API processes the request and fetches or updates data.
5. 5API response: the API sends the response back (often JSON).
6. 6Client receives: the client receives and uses the data.

Key points

• Uses standard methods (GET, POST, PUT, DELETE) over HTTP/HTTPS.
• Secured with API keys, OAuth, JWT and more.
• Reusable across multiple apps and platforms.
• Scalable — handles many requests with caching and rate limiting.

Why it matters

APIs are how modern software — including AI tools and agents — connects to services and data. Understanding them is essential for building anything that integrates with the outside world.

Frequently asked questions

Why do AI agents need APIs?

Agents call APIs to take real actions and fetch real data — search, databases, email and more.

What is an endpoint?

A specific URL the API exposes for a particular action, like /users to get user data.