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Curl to JSON Converter

Convert curl commands to JSON and fetch

Last Updated: March 2, 2026
avatarBy Viblaa Team

JSON output

Fetch API code

Header parsing

Body extraction

The API documentation shows a curl example. Your application uses JavaScript fetch. The example has 12 headers, a complex POST body, and authentication. Translating by hand means typos, forgotten headers, and frustrating debugging.

Curl commands are the universal language of API examples. But when you need fetch(), Axios, or a structured JSON object, manual translation is tedious and error-prone. This converter parses curl instantly, giving you the format your code actually needs.

What is Curl to JSON Conversion?

This tool parses curl command-line syntax and extracts the structured components: URL, HTTP method, headers, body, and authentication. It outputs these as a clean JSON object or generates equivalent JavaScript fetch code.

Conversion example:

# Input: curl command
curl -X POST "https://api.example.com/users" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer token123" \
  -d '{"name":"John"}'

# Output: JSON
{
  "url": "https://api.example.com/users",
  "method": "POST",
  "headers": {
    "Content-Type": "application/json",
    "Authorization": "Bearer token123"
  },
  "body": {"name": "John"}
}
Curl Is the API Lingua Franca

Nearly every API doc includes curl examples because curl is universal. Converting these to your actual HTTP client saves time and reduces errors.

Why People Actually Need This Tool

Copy-Paste API Integration

Most API integration starts with copying documentation examples. Converting curl to your actual codebase's HTTP client is where mistakes happen.

  1. API integration — Convert documentation examples to usable code.

  2. Debugging exports — Browser DevTools export requests as curl; convert for analysis.

  3. Testing automation — Transform curl test cases to Postman or code.

  4. Documentation creation — Generate structured JSON from curl examples for docs.

  5. Code generation — Get fetch() or Axios code instead of curl.

  6. Request analysis — Parse complex curl commands to understand all components.

  7. Cross-platform work — Convert shell commands to language-native requests.

How to Use Curl to JSON Converter

  1. Paste your curl command — From documentation, DevTools, or anywhere.

  2. Parse instantly — See structured breakdown of all request components.

  3. Choose output format — JSON object, fetch code, or Axios code.

  4. Copy and use — Integrate directly into your application.

Curl FlagParsed AsPurpose
-X, --requestHTTP methodGET, POST, PUT, DELETE
-H, --headerHeaders objectContent-Type, Auth, etc.
-d, --dataRequest bodyPOST/PUT payload
-u, --userBasic authusername:password
-b, --cookieCookiesSession cookies
-L, --locationFollow redirectsRedirect handling flag
Secrets in Curl Commands

Curl commands from DevTools often include auth tokens and session cookies. Be careful when sharing parsed output—it may contain sensitive credentials.

Real-World Use Cases

1. The API Documentation Integration

Context: Integrating a payment API. Docs show curl examples only.

Problem: Application uses Axios. Manual translation risks typos in header names.

Solution: Paste curl, get Axios code with correct headers and body structure.

Outcome: Working integration in minutes instead of debugging header typos for hours.

2. The Browser Debug Export

Context: Debugging why a request works in browser but fails in code.

Problem: DevTools shows "Copy as cURL" but code uses fetch().

Solution: Copy curl from DevTools, convert to fetch() to see exact equivalent.

Outcome: Discover missing header that browser sends automatically but code didn't.

3. The Postman Import

Context: Team sharing API test cases. Some use curl, some use Postman.

Problem: Need curl examples converted to Postman collections.

Solution: Convert curl to JSON, import structured data into Postman.

Outcome: Unified test collection everyone can use regardless of preferred tool.

4. The Webhook Testing

Context: Testing webhook endpoint with specific payload structure.

Problem: Webhook provider gives curl examples; need to reproduce in test suite.

Solution: Parse curl to understand exact headers and body structure.

Outcome: Test suite matches production webhook behavior exactly.

5. The Legacy System Analysis

Context: Inheriting codebase with curl commands embedded in shell scripts.

Problem: Need to understand what each curl command actually does.

Solution: Parse each command to see structured breakdown of URL, method, headers.

Outcome: Document all API dependencies in the legacy system.

6. The GraphQL Query Extraction

Context: GraphQL API documented with curl POST examples.

Problem: Need to extract the query from the curl body for a GraphQL client.

Solution: Parse curl, extract body, format GraphQL query cleanly.

Outcome: Query ready for GraphQL client without manual JSON parsing.

7. The Multi-Language Support

Context: SDK needs examples in Python, JavaScript, Go, and Ruby.

Problem: Writing same request in 4 languages manually is error-prone.

Solution: Start with curl, convert to JSON, generate each language from structure.

Outcome: Consistent examples across all languages from single source of truth.

Common Mistakes and How to Avoid Them

Curl Has Many Dialects

Windows curl, Git Bash curl, and macOS curl handle quoting differently. Make sure the command is valid for your environment.

Including Shell Variables
❌ The Mistake
Parsing curl with unexpanded variables like `$API_KEY` that can't be converted.
âś… The Fix
Expand variables before parsing, or replace them with placeholder values.
Mixing Quote Styles
❌ The Mistake
Curl command with mixed single and double quotes from different sources.
âś… The Fix
Normalize quoting style before parsing. Most parsers prefer double quotes for JSON.
Forgetting Authentication Context
❌ The Mistake
Converting curl with `-u user:pass` but not handling Basic auth correctly in output.
âś… The Fix
Basic auth becomes Authorization header with base64 encoding. Verify conversion handles this.
Copying Production Tokens
❌ The Mistake
Sharing converted output that includes real API tokens or session cookies.
âś… The Fix
Review converted output for sensitive data. Replace real tokens with placeholders before sharing.
Ignoring Request Body Encoding
❌ The Mistake
Assuming body is JSON when curl used form encoding (`-F` or `--form`).
âś… The Fix
Check Content-Type. Form data needs different handling than JSON in most HTTP clients.

Privacy and Data Handling

This Curl to JSON Converter operates entirely in your browser.

  • No curl commands are sent to any server.
  • No requests are logged or stored.
  • No account required.
  • Works completely offline.

Parse curl commands with authentication tokens safely—nothing leaves your device.

Conclusion

Curl commands are everywhere: documentation, StackOverflow answers, DevTools exports, debugging guides. But your application probably doesn't use curl. It uses fetch, Axios, requests, or whatever your language prefers.

This converter bridges that gap. Paste any curl command—no matter how complex—and get structured data you can actually use. No more typos from manual translation, no more missing headers, no more debugging simple mistakes.

Let machines do the translation. You focus on the integration.

Frequently Asked Questions