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API Header Builder & cURL Generator

Build HTTP requests visually and generate code for cURL, fetch, axios, and Python with headers, auth, and query params

API Header Builder & cURL Generator

Request builder

Headers

Query parameters

curl -X GET \
  -H "Content-Type: application/json" \
  -H "Accept: application/json"
  "https://api.example.com/users"

Quick tips

  • • Use common headers dropdown for quick additions
  • • Query params are automatically URL-encoded
  • • Click "Format JSON" to beautify your request body
  • • Authentication headers are automatically added to generated code
  • • All generated code is ready to copy and use in your project

Updated . Provided as is. Check the output before you rely on it in production.

How to use API Header Builder & cURL Generator

  1. 1

    Select HTTP method

    Choose GET, POST, PUT, DELETE, PATCH, or other methods. The method determines what kind of request you're building.

  2. 2

    Build request headers

    Add headers: Content-Type (application/json, application/x-www-form-urlencoded), Authorization (Bearer token, Basic auth), and custom headers your API requires.

  3. 3

    Add request body (if needed)

    For POST/PUT/PATCH, include a JSON body or form data. The tool structures it correctly and validates JSON syntax.

  4. 4

    Generate cURL command

    The tool outputs a ready-to-use cURL command: curl -X POST https://api.example.com/endpoint -H 'Authorization: Bearer token' -d '{...}'. Copy and run in terminal.

  5. 5

    Convert to code

    Switch the output to JavaScript fetch, axios, Python requests or raw HTTP, then paste it into your codebase.

Questions and answers

What is API Header Builder & cURL Generator?
HTTP request headers carry metadata such as Content-Type, Accept and Authorization alongside the method, URL and body. This builder assembles a request from a form, with Bearer, Basic or API key auth, query parameters and a body, and writes it as cURL, fetch, axios, Python requests or raw HTTP.
Does API Header Builder & cURL Generator store or send my data?
No. All processing happens entirely in your browser. Your API details and credentials stay on your device — nothing is sent to any server.
What code output formats are supported?
It generates code for cURL (terminal), JavaScript fetch, JavaScript axios, and Python requests. Each output includes the full request configuration with headers, auth, query params, and body.

Use it as an API

API Header Builder & cURL Generator is also callable as a free HTTP JSON API at https://aidevhub.io/api/api-header-builder/ — GET with query parameters or POST with a JSON body, no authentication, CORS enabled, fair use (abusive traffic is throttled at the edge; there is no per-request quota header). Responses return { ok, tool, result, meta }. 

curl -s "https://aidevhub.io/api/api-header-builder/?url=https%3A%2F%2Fapi.example.com%2Fusers&method=GET&lang=fetch"

Machine-readable contract: /api/tool/api-header-builder.json All API endpoints: /agents/ LLM site index: /llms.txt

For AI agents: how to call this tool

Machine-readable contract, endpoints and examples. Humans can ignore this section.

Best Path For Builders

Dedicated API endpoint

Deterministic outputs, machine-safe contracts, and production-ready examples.

Dedicated API

https://aidevhub.io/api/api-header-builder/

OpenAPI: https://aidevhub.io/api/openapi.yaml

GET /api/api-header-builder/ GET api-header-builder
POST /api/api-header-builder/ POST api-header-builder