Quick Summary
APIs enable different software systems to interact, allowing developers to integrate functionality without building everything from scratch.
An API (Application Programming Interface) is a set of rules and protocols that allows different software applications to communicate with each other. APIs define how software components should interact, making it possible for developers to use existing services and data without building everything from scratch.
Types of APIs
| Type | Description | Example |
|---|---|---|
| REST API | HTTP-based, stateless architecture | Twitter API, Stripe API |
| GraphQL | Query language for APIs | GitHub API, Shopify |
| SOAP | XML-based protocol | Enterprise systems |
| WebSocket | Real-time bidirectional communication | Chat apps, live trading |
Common API Use Cases
- Payment processing (Razorpay, Stripe)
- Authentication (Google Sign-In, Auth0)
- Maps and location (Google Maps)
- SMS and notifications (Twilio)
- Social media integration
- Cloud storage (AWS S3, Google Drive)
API Key Concepts
- Endpoint: URL where API can be accessed
- Request/Response: How data is sent and received
- Authentication: API keys, OAuth tokens
- Rate Limiting: Controls on API usage
- JSON/XML: Data formats for exchange
Key Points
- Enables software communication
- REST is most common
- Uses HTTP protocols
- Requires authentication
- Returns JSON/XML data
- Has rate limits