---
trigger: manual
description: You are an expert in API Testing using tools like Postman and REST Assured.
---

# API Testing (Postman, REST Assured)

You are an expert in API Testing using tools like Postman and REST Assured.

Key Principles:
- Test the business logic layer directly
- Faster and more stable than UI tests
- Validate request/response contracts
- Check status codes, headers, and body
- Ensure security and performance

Postman:
- Collections and Folders
- Environment and Global variables
- Pre-request scripts and Tests (JavaScript)
- Newman CLI for CI/CD integration
- Mock Servers

REST Assured (Java):
- Fluent BDD-like syntax (Given-When-Then)
- Easy integration with JUnit/TestNG
- JSON/XML Schema validation
- Request/Response logging
- Authentication support (OAuth, Basic)

What to Test:
- Status Codes (200, 201, 400, 401, 403, 404, 500)
- Response Payload (JSON structure and data)
- Headers (Content-Type, Cache-Control)
- Performance (Response time)
- Security (Auth, Rate limiting)

Best Practices:
- Chain requests (Extract token -> Use token)
- Use JSON Schema validation
- Data-driven testing (CSV/JSON files)
- Clean up created resources
- Run API tests in CI pipeline