Curl to Fetch Converter

What is a Curl to Fetch Converter?

A curl to fetch converter transforms curl commands into JavaScript fetch() API calls and vice versa. This is essential when you have a working curl command from API documentation or debugging and need to implement it in your JavaScript or TypeScript application. The tool handles bidirectional conversion, preserving HTTP methods, headers, authentication, and request bodies.

How to Use

Curl to Fetch:

1. Paste your curl command in the input field
2. Select output language (JavaScript or TypeScript)
3. Choose whether to include error handling and comments
4. Click "Convert to Fetch" to generate the code
5. Copy the generated fetch() code into your application

Fetch to Curl:

1. Switch to the "Fetch → Curl" tab
2. Paste your fetch() code in the input field
3. Click "Convert to Curl" to generate the command
4. Copy the curl command for testing in terminal

Example: Converting GET Request

Curl command:

curl 'https://api.github.com/users/octocat' -H 'Accept: application/json'

Generated JavaScript fetch:

fetch('https://api.github.com/users/octocat', {
  method: 'GET',
  headers: {
    'Accept': 'application/json'
  }
})
  .then(response => response.json())
  .then(data => console.log(data));

Example: Converting POST with JSON

Curl command:

curl -X POST 'https://api.example.com/users' \
  -H 'Content-Type: application/json' \
  -d '{"name":"John","email":"john@example.com"}'

Generated TypeScript fetch:

async function makeRequest() {
  const response = await fetch('https://api.example.com/users', {
    method: 'POST' as const,
    headers: {
      'Content-Type': 'application/json'
    },
    body: '{"name":"John","email":"john@example.com"}'
  });
  const data = await response.json();
  return data;
}

Example: Converting Authenticated Request

Curl command:

curl 'https://api.example.com/protected' \
  -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9'

Generated JavaScript fetch:

fetch('https://api.example.com/protected', {
  method: 'GET',
  headers: {
    'Authorization': 'Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9'
  }
})
  .then(response => response.json())
  .then(data => console.log(data));

JavaScript vs TypeScript Output

• JavaScript: Uses promise chains (.then/.catch) and standard fetch syntax
• TypeScript: Wraps code in async function, uses await syntax, includes type annotations

Error Handling Options

• With error handling: Includes response.ok check, try/catch blocks, and error logging
• Without error handling: Minimal code for quick prototyping

Common Use Cases

• API Integration: Convert curl examples from API docs into application code
• Debugging: Test API calls in terminal, then implement in code
• Code Migration: Modernize shell scripts to use fetch() API
• Documentation: Provide both curl and fetch examples for APIs
• Testing: Convert application requests to curl for reproduction

Supported Features

• All HTTP methods (GET, POST, PUT, DELETE, PATCH, HEAD, OPTIONS)
• Custom headers including authentication
• Request bodies for POST/PUT/PATCH
• Bearer token authentication
• Basic authentication
• API key headers
• Content-Type headers

Limitations

• Does not support curl's advanced flags (-v, -L, -k, etc.)
• Does not handle file uploads or multipart form data
• Does not support curl's --data-binary or --data-raw flags
• Fetch to curl conversion requires standard fetch() syntax

Privacy Notice

All conversions happen entirely in your browser. Your curl commands, fetch code, URLs, headers, and authentication tokens are never transmitted to any server. This ensures complete privacy when working with sensitive API credentials.