API Development Guide

Introduction

This guide walks you through the essential steps to design, build, secure, test, and deploy robust APIs.

REST Design Principles

Follow these conventions to create intuitive and maintainable RESTful services.


// Example Express route
app.get('/api/v1/users/:id', (req, res) => {
  const user = getUserById(req.params.id);
  if (!user) return res.status(404).json({ error: 'Not found' });
  res.json(user);
});

Authentication & Authorization

Prefer token‑based approaches like JWT. Keep secrets out of the client.


const jwt = require('jsonwebtoken');
function authenticate(req, res, next) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.sendStatus(401);
  try {
    req.user = jwt.verify(token, process.env.JWT_SECRET);
    next();
  } catch {
    res.sendStatus(403);
  }
}

Versioning

Include the version in the URL or header. Example: /api/v1/….

Testing

Automate with tools like Jest and SuperTest for integration tests.


const request = require('supertest');
const app = require('../app');

test('GET /api/v1/users/:id returns user', async () => {
  const res = await request(app).get('/api/v1/users/1');
  expect(res.statusCode).toBe(200);
  expect(res.body).toHaveProperty('id', '1');
});

Documentation

Use OpenAPI/Swagger to generate interactive docs.

OpenAPI Specification

Deployment

Containerize with Docker and orchestrate with Kubernetes or serverless platforms.

Live Example

Click the button to fetch a random joke from https://official-joke-api.appspot.com/random_joke.