API Design Basics

How it works

Overview

Focus on consistent resource naming, status codes, error shapes, and compatibility via versioning.

Learning Objectives

🎯 RESTful Design Principles

Master REST architectural constraints and design consistent, intuitive APIs that follow industry standards

🔧 Versioning & Evolution

Learn API versioning strategies and backward compatibility techniques for seamless API evolution

⚡ Error Handling & Documentation

Understand comprehensive error handling patterns and API documentation best practices

Real-World Examples

🌐 GitHub API Evolution

GitHub's REST API v4 maintains backward compatibility while introducing GraphQL, using versioning headers and deprecation notices

Benefit: 99.9% client compatibility during transitions

💳 Stripe Payment API

Stripe's API design emphasizes consistent resource modeling and comprehensive error codes, making integration predictable

Benefit: 80% reduction in integration support tickets

☁️ AWS Service APIs

AWS uses consistent naming conventions and pagination patterns across all services, enabling unified SDK development

Benefit: 70% code reuse across service integrations

🏪 Shopify REST API

Shopify's API includes rate limiting, webhook subscriptions, and detailed error responses for robust e-commerce integrations

Benefit: 95% successful third-party app integrations

Code example

Versioned REST endpoints with a standard error contract using Express.js:

const express = require('express');
const app = express();

// v1 - users resource
app.get('/v1/users/:id', function (req, res, next) {
  // lookup user...
  res.json({ id: req.params.id, name: 'Alice' });
});

// Standard error shape
app.use(function (err, req, res, next) {
  var status = err.status || 500;
  res.status(status).json({ error: { code: status, message: err.message } });
});

app.listen(3000);

Implementation Notes

Use semantic versioning in URLs (/v1/, /v2/) or headers (Accept: application/vnd.api+json;version=1)
Implement consistent HTTP status codes (200, 201, 400, 404, 500) across all endpoints
Design resource URLs following RESTful conventions (nouns, not verbs)
Include pagination metadata (total_count, next_page) for collection endpoints
Use content negotiation for different response formats (JSON, XML, CSV)

Best Practices

Provide comprehensive API documentation with examples and error scenarios
Implement rate limiting and include limit headers in responses
Use consistent naming conventions (snake_case or camelCase) throughout the API
Include request tracing IDs for debugging and support purposes
Validate input thoroughly and return descriptive error messages

Common Pitfalls

Breaking backward compatibility without proper deprecation notices and migration paths
Using inconsistent error response formats that make client error handling difficult
Returning sensitive information in error messages or API responses
Not implementing proper authentication and authorization for protected resources
Ignoring caching headers and performance optimization for frequently accessed endpoints