Building a simple api does not require complicated server configurations, cloud infrastructure, or enterprise frameworks. With just a few lines of JavaScript, you can spin up an HTTP server that listens for incoming client requests and responds with formatted JSON.

Building a Simple API in Node.js (Zero Dependencies)

You don't even need external packages like Express to create a simple api. Node.js has a built-in node:http module:

// server.js - A minimal, production-valid Simple API
import http from 'node:http';

const server = http.createServer((req, res) => {
  // Set CORS and JSON response headers
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Content-Type', 'application/json');

  if (req.method === 'GET' && req.url === '/api/quote') {
    const quotes = [
      { text: "Simplicity is the soul of efficiency.", author: "Austin Freeman" },
      { text: "Make it work, make it right, make it fast.", author: "Kent Beck" }
    ];
    const randomQuote = quotes[Math.floor(Math.random() * quotes.length)];
    
    res.writeHead(200);
    return res.end(JSON.stringify({ status: 'ok', data: randomQuote }));
  }

  // Fallback 404 handler
  res.writeHead(404);
  res.end(JSON.stringify({ error: 'Endpoint not found' }));
});

server.listen(3000, () => {
  console.log('Simple API running on http://localhost:3000/api/quote');
});

Calling Your Simple API with Fetch

Once running, any browser or frontend app can consume your simple api with native fetch():

const response = await fetch('http://localhost:3000/api/quote');
const json = await response.json();
console.log(json.data.text); // "Simplicity is the soul of efficiency."

That is all it takes! A simple api boils down to receiving a URL route, checking the HTTP method, and writing back a response stream.