An HTTP Request Composer is a tool that lets you construct and send HTTP requests to servers or APIs directly from your browser. You can choose the HTTP method, set headers, define the request body, and inspect the full response including status codes, headers, and body. It’s perfect for API testing and debugging.

CORS (Cross-Origin Resource Sharing) errors occur when a web application tries to access a resource from a different origin (domain, protocol, or port) that doesn't permit the request. This is a browser security feature. To fix it, the server must include appropriate CORS headers, or you can use a CORS proxy. Many public APIs already support CORS for test environments.

x-www-form-urlencoded sends data as key-value pairs encoded in the URL (for GET) or in the request body (for POST). It’s suitable for simple text data. form-data (multipart/form-data) is used when you need to send binary files or when the data is larger. Each form field is sent as a separate part with its own headers.

Select the Raw (JSON/Text/XML) body type and manually enter your JSON payload in the text area. Make sure to set the Content-Type: application/json header (the tool adds it by default). The JSON will be sent exactly as you type it.

This tool doesn't store data permanently. However, you can generate a cURL command by clicking “Copy cURL” and save it in your notes or terminal history. Many developers use cURL to reproduce requests quickly.