Curl Fetch Api Converter

Fast, accurate and free online curl fetch api converter tool running directly in your browser.

Secure (SSL)

Client-Side Processing

100% Free

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Instructions

1

Enter data
Enter content, paste text or load a file from disk.
2

Click the button
The tool will immediately process your data in the browser.
3

Get the result
Copy the finished text or save the file to your device.

                                                function runTool() {

                                                  return "Result ready in 0.1s";

                                                }

Settings

Output lang

Body mode

Curl

Use await Tool Option

Credentials Tool Option

Readable formatting Tool Option

Result

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cURL to Fetch API Converter - JavaScript ES6+ in a Second

The cURL command is a terminal tool for sending HTTP requests - perfect for testing APIs from the command line. Fetch API is a native browser standard and Node.js for the same purpose. The tool translates cURL syntax (flags -H, -d, -X, -u) into equivalent JavaScript code from async/await or Promise chain.

cURL to Fetch converter curl to fetch JS convert curl to JavaScript fetch API converter

cURL to Fetch flag mapping

curl -X POST → method: "POST". curl -H "Content-Type: application/json" → headers: {"Content-Type":"application/json"}. curl -d '{"key":"val"}' → body: JSON.stringify({key:"val"}). curl -u user:pass → headers: {Authorization: "Basic "+btoa("user:pass")}. curl -b "cookie=val" → headers: {Cookie: "cookie=val"}.

Authorization - all types

Bearer token: curl -H "Authorization: Bearer TOKEN" → headers: {Authorization: "Bearer TOKEN"}. Basic auth: curl -u user:pass → btoa("user:pass"). API Key in header: -H "X-API-Key: KEY" → headers: {"X-API-Key":"KEY"}. OAuth: like Bearer. Cookie-based: -b "session=abc" → credentials: "include" + appropriate header.

Error handling in Fetch

Fetch does NOT throw an exception on HTTP 4xx/5xx responses - only on network errors. Valid pattern: if (!response.ok) throw new Error(response.status). The tool generates code with error handling: try/catch + response.ok check + logging.

Node.js vs browser

In browser: native fetch (all modern browsers + IE11 with polyfill). Node.js 18+: native fetch (global object). Node.js < 18: node-fetch or axios package. The tool generates code compatible with both platforms (ES2017 async/await).

FAQ

What are the limitations of Fetch vs cURL?

CORS (Cross-Origin Resource Sharing): The browser blocks requests to other domains without the Access-Control-Allow-Origin header. cURL does not have this limitation (it works server-side). Solution: proxy your own endpoint or use cURL for direct API calls from the backend.

How to convert multipart/form-data in cURL?

curl -F "[email protected]" → new FormData() + append("file", fileBlob). curl -F "field=value" → formData.append("field","value") + fetch(url, {method:"POST", body: formData}). Don't set Content-Type manually - the browser will set it with the boundary.

What is the difference between Fetch and XMLHttpRequest?

XMLHttpRequest (XHR): old API, callback-based, works in IE. Fetch: Promise-based, more readable, supports async/await, no onprogress for upload (also ReadableStream or XHR). Axios wraps XHR but has a similar interface to Fetch.

Does Fetch support timeout?

Natively no. Workaround: AbortController + AbortSignal.timeout(5000) (Chrome 103+): fetch(url, {signal: AbortSignal.timeout(5000)}). Or manually: const controller = new AbortController(); setTimeout(()=>controller.abort(), 5000); fetch(url, {signal: controller.signal}).

How to debug Fetch requests in Chrome DevTools?

Network tab → Fetch/XHR. Click on request → Headers, Payload, Response, Timing. Copy as cURL: right click → Copy → Copy as cURL (can be pasted here for conversion). Console: window.fetch = ... for monkey-patching.

Related tools: Fetch API to cURL converter, test JSON API generator and JSON validator.