REST API Automation Testing – Full Beginner Guide with Examples
By Bhau Automation • API Testing & REST Automation Tutorial
🎯 Topics Covered in This Tutorial
- What is an API? (Real-life example)
- REST API basics
- Core principles of REST Architecture
- HTTP methods (GET, POST, PUT, DELETE)
- REST API automation testing tools
- Best practices for API testing
- Interview questions
📌 What is an API?
An API (Application Programming Interface) allows two applications to communicate with each other. It works as a bridge between client and server.
Real-life Example:
- Mobile app → API → Database
- ATM Machine → Bank Server via API
- Payment Gateway → Website
📌 What is REST API?
A REST API follows principles like statelessness, client-server architecture, cacheability and uniform interface.
REST Principles:
- Stateless communication
- Resource-based architecture
- Client-server separation
- JSON/XML data formats
🌐 HTTP Methods Explanation
| Method | Purpose |
|---|---|
| GET | Fetch data |
| POST | Send data |
| PUT | Update data |
| DELETE | Remove record |
🧪 REST API Testing Tools
- Postman
- Rest Assured
- SOAP UI
- JMeter
- Cypress API
✅ Best Practices
- Validate status codes
- Automate regression tests
- Secure APIs using tokens
- Maintain logs
- Use frameworks
❓ Important Interview Questions
Q: What is REST?
REST is an architectural style for APIs.
Q: Which tool is best for API automation?
Rest Assured and Postman.
Q: What is difference between API and Web Service?
All web services are APIs but not all APIs are web services.
REST is an architectural style for APIs.
Q: Which tool is best for API automation?
Rest Assured and Postman.
Q: What is difference between API and Web Service?
All web services are APIs but not all APIs are web services.
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✅ Key Takeaways
- APIs power modern applications
- REST API is industry standard
- Automation reduces manual work
- Testing ensures reliability
🚀 Created with ❤️ by Bhau Automation