API Development & Debugging Guide
APIs (Application Programming Interfaces) connect frontend apps, mobile apps, and backend databases. Building and debugging APIs requires inspecting HTTP headers, formatting payloads, and testing curl commands.
1. Core API Concepts
Every HTTP request consists of basic parts: - **HTTP Method:** `GET` to fetch data, `POST` to create, `PUT` to update, `DELETE` to remove. - **URL Path:** The endpoint address you are requesting. - **Headers:** Metadata like `Authorization`, `Content-Type`, and `Cache-Control`. - **Body:** Data payload sent in JSON or form format.
2. Converting curl to Code
Developers often copy curl commands from documentation. You can convert curl commands directly into: - `fetch()` syntax for modern browser JavaScript. - `axios` calls for Node.js and React apps. - Python `requests` calls for automation scripts.
3. Mocking Responses
Mocking lets frontend engineers build UI features before backend endpoints are ready: - Define sample status codes (`200 OK`, `404 Not Found`, `500 Error`). - Generate realistic mock JSON payloads with sample user lists and products.
Engineering Best Practices & Guidelines
Always set `Content-Type: application/json` when sending JSON payloads.
Use Bearer tokens in the `Authorization` header for secure API requests.
Test error responses (like 400 and 500) to make sure your frontend handles failures smoothly.
Use our free curl converter tools to turn terminal commands into clean JavaScript code.
Frequently Asked Questions
Q1. What is the difference between GET and POST?
GET requests fetch data from a server without modifying it. POST requests send data to the server to create or process a record.
Q2. How do I convert a curl command to JavaScript fetch?
Paste your curl string into our free curl-to-fetch tool. It parses the URL, method, headers, and body into clean JavaScript code.