Outline for API Documentation of Basic Express Server Overview Introduction to the Basic Express Server Purpose of the API Technology Stack Getting Started Prerequisites Node.js NPM (Node Package Manager) Installation Instructions Cloning the Repository Installing Dependencies Starting the Server API Endpoints Endpoint Structure and Naming Conventions Base URL 3.1 Testing Route Endpoint : /test Method : POST Description : Endpoint to test server with a sample request payload and response. Request Payload : Content-Type: application/json **Sample Payload**: json message": "Hello, World!" **Request Parameters**: `message` (string): A message to be echoed back. *Response**: **Status Code**: 200 OK **Content-Type**: `application/json` **Sample Response**: ``json echo": "Hello, World!" `` **Response Parameters**: `echo` (string): An echoed message similar to the request. Error Handling Error Response Format Common Error Codes 400 Bad Request 404 Not Found 500 Internal Server Error Testing Setting Up Testing Environment Testing Libraries Used (e.g., Mocha, Chai) Running Tests Sample Test Case for Testing Route Best Practices Security Considerations Performance Tips Troubleshooting Common Issues and Solutions Conclusion Summary of the API Capabilities Additional Resources Links to Express.js Documentation Tutorials and Guides Change Log Version History Major Updates and Fixes