CodingPremise
Explore free tools
APIs · Intermediate

REST API Basics: HTTP, JSON & Requests

Understand HTTP methods, status codes, JSON payloads and common API integration pitfalls.

An API defines how software components exchange data. Read a service’s contract, validate errors and use appropriate authentication before shipping integrations.

What you will learn

  1. HTTP methods and endpoints
  2. Request and response JSON
  3. Error handling and security
CHAPTER 01

HTTP methods and endpoints

GET fetches resources; POST often creates them; PUT and PATCH update representations; DELETE removes resources. Real API semantics are documented by each provider.

GET /api/projects
POST /api/projects
PATCH /api/projects/42
CHAPTER 02

Request and response JSON

Use Content-Type headers appropriately and parse JSON only when the response actually contains JSON. Client input must always be validated by the server.

fetch("/api/projects")
  .then(response => response.json())
  .then(data => console.log(data));
CHAPTER 03

Error handling and security

Handle non-200 statuses, network failures and throttling. Protect secrets by calling authenticated upstream APIs from a backend, not a public webpage.

const response = await fetch("/api/projects");
if (!response.ok) throw new Error(`HTTP ${response.status}`);

Practice the concepts

Use a related utility to experiment, check examples, and build a small project.

Explore JSON formatter ↗