HTTP & APIs

Understand how software systems communicate through requests, URLs, API endpoints, and responses.

Module goals

Read a URLRecognize the path, query string, and values inside a web address.

Follow a requestUnderstand how a client asks an API for data or an action.

Connect the layersSee how HTTP carries information between frontend and backend services.

Client→HTTP Request→API Endpoint→Backend→HTTP Response

HTTP is the communication protocol; an API defines the available way to ask a system for data or actions.

The protocol used to exchange messages on the web.

The address that identifies a page, resource, or API endpoint.

A defined interface for software-to-software communication.

The message asking for data or an action.

The result returned after a request is processed.

A URL value that filters, searches, sorts, or controls results.

Method+URL+Headers / Body→Request→Response

A request combines an action with an address and optional information. The response reports what happened and can return data.

POSTAn HTTP method commonly used to create or submit data.

HTTP & APIs GlossaryReview shared HTTP, API, request, response, and data vocabulary.

An HTTP method commonly used to update selected fields of an existing resource.

Only the fields that need to change have to be sent.

An HTTP method commonly used to remove a resource.

Review the full DELETE topic and its request flow.

GETAn HTTP method commonly used to retrieve data.