Client
API
API Contract
Client asks. API responds. Your UI updates.
APIs separate what you ask for from how the backend does it.

What Is an API?

Think of an API as a restaurant menu. The menu tells you what you can ask for. The kitchen does the hard work. Your app is the customer, and the server is the kitchen.

Endpoint = Exact Address

To talk to an API, you call a URL endpoint. It works like a house address. If the address is wrong, your request never reaches the right destination.

Requests Need Intention

You send requests with an HTTP method. GET usually reads data. POST creates data. PATCH updates. DELETE removes.

Responses Bring Data Back

The server answers with status + payload. Status says if the request worked. Payload contains the data your UI can render.

Most APIs Are Protected

Many APIs require credentials so only authorized apps can access them. Common options are API keys and Bearer tokens.

Errors Are Normal

APIs fail sometimes: bad input, expired tokens, network issues, rate limits. Good apps handle these gracefully and keep users informed.

API Foundations Ready

You can now read API docs with confidence and understand how requests, responses, and auth fit together in real apps.

AlgoAnimator: Interactive Data Structures