Understanding Web APIs
Learn how applications communicate across the internet
Web APIs (Application Programming Interfaces) are the bridges that allow different software applications to communicate with each other over the internet. They define the rules, protocols, and tools for how applications can request and exchange data.
Learning Objectives
You'll understand REST principles, API authentication, rate limiting, and how to work with real APIs through hands-on demonstrations using a weather API example.
Real-world analogy:
Think of APIs like a restaurant menu and waiter. The menu (API documentation) tells you what you can order and how. You make requests to the waiter (API endpoint) who brings back your food (data) from the kitchen (server).
1REST API Fundamentals
HTTP Methods & Their Purposes
2API Authentication & Security
How API Keys Work
API keys are unique identifiers that authenticate your requests. Think of them like a membership card that proves you're allowed to use the service.
Example API Request with Key:
Host: api.example-weather.com
X-API-Key: wth_9a8b7c6d5e4f3g2h1i0j9k8l7m6n5o4p
Security Tip: Never share your API keys publicly or commit them to GitHub. Treat them like passwords!
What happens without a valid key?
3Rate Limiting & Usage Control
Rate Limit Information
Common Rate Limit Headers:
X-RateLimit-Remaining: 350
X-RateLimit-Reset: 1642680000
// Reset time as Unix timestamp
4Complete API Simulation
📝 Note: Simulated Environment
This is a simulation showing how real APIs work. No actual API calls are made - all responses are generated locally for learning purposes.
Interactive Weather API Demo
Best Practices Demonstrated:
- RESTful URLs: Clear, predictable endpoint structure
- Proper HTTP methods: GET for retrieval, POST for creation
- Authentication: API key included in headers
- Error handling: Meaningful error messages and status codes
- Rate limiting: Respectful request frequency
Summary
You've now explored the complete Web API ecosystem through interactive demonstrations:
- REST Fundamentals: HTTP methods, endpoint design, and resource-based URLs
- Authentication: API keys, bearer tokens, and secure request methods
- Rate Limiting: Usage control, quota management, and error handling
- Real Implementation: Complete API integration with best practices