Toolpaper

Convert a cURL PATCH request to JavaScript

Paste any curl PATCH command and get clean JavaScript code using fetch. Runs entirely in your browser — headers, auth, and JSON bodies map to idiomatic JavaScript.

Quick answer

To convert a cURL command to JavaScript, paste it into the Toolpaper workbench below. It parses the command in your browser and emits idiomatic JavaScript code — headers, query string, request body, authentication (Bearer, Basic, API key), and cookies are all wired up automatically. No data is uploaded; conversion is fully client-side.

Prefer a different target? See the full cURL to JavaScript reference, or jump to the same guide in Node.js, Python, or Go.

InputcURL command
MethodPATCH·Headers1·Body27 B· Chars 123
OutputJavaScript · fetch(browser/Node)
const response = await fetch("https://api.example.com/users/42", {
  method: "PATCH",
  headers: {
    "Content-Type": "application/json"
  },
  body: "{\"email\":\"ada@example.com\"}",
  redirect: "manual"
});
const data = await response.json();
Inspect

Example

A representative curl command for this scenario. Paste your own above to convert an exact match.

curl input
curl -X PATCH https://api.example.com/users/42 \
  -H "Content-Type: application/json" \
  -d '{"email":"ada@example.com"}'

Implementation notes

  • Request-line method (PATCH) and target URL are extracted from the curl command exactly as written — no case-folding, no path rewriting.
  • Every -H header maps to a JavaScript header entry; duplicates are preserved so servers that read multi-valued headers keep behaving.
  • Query strings in the URL stay in the URL; -G with --data-urlencode is promoted to a structured params argument where fetch supports it.
  • Request bodies are parsed against Content-Type: JSON bodies use idiomatic serialization (fetch), form bodies use URL-encoding, multipart uses -F semantics with file@ handling.
  • TLS flags (--insecure, --cacert, --cert) surface as inline notes so you don't ship an insecure client to production by accident.

Common mistakes

  • Forgetting that -X PATCH without a body still sends an empty body — the generated code mirrors that exactly.
  • Assuming curl auto-follows redirects: it doesn't. Add -L (or the generator's follow-redirects flag) if you actually need to chase 3xx responses.
  • Copying a Cookie header from DevTools that already encodes session state — use the Clean panel to strip session cookies before you share.

Common questions

How do I send a PATCH request in JavaScript?
Paste your curl PATCH command above. Toolpaper generates JavaScript using fetch with headers, query string, and (where applicable) request body wired up.
Does the PATCH generator handle authentication?
Yes — Authorization headers, Bearer tokens, Basic auth (-u), and API keys pass through to the generated JavaScript code unchanged.
Is my curl sent to a server?
No. Parsing and code generation run in your browser. Nothing is uploaded.
Can I also convert this to other languages?
Yes. Once you paste your command, the language picker lets you switch between 18 targets (fetch, axios, Python, Go, PHP, Ruby, Rust, Java, Kotlin, C#, PowerShell, Swift and more).

More cURL methods in JavaScript

JavaScript hub →

GET in JavaScript

/how-to/curl-get-in-javascript

POST in JavaScript

/how-to/curl-post-in-javascript

PUT in JavaScript

/how-to/curl-put-in-javascript

DELETE in JavaScript

/how-to/curl-delete-in-javascript

The same guide in other languages

All guides →

In Node.js

/how-to/curl-patch-in-node

In Python

/how-to/curl-patch-in-python

In Go

/how-to/curl-patch-in-go

In PHP

/how-to/curl-patch-in-php

In Ruby

/how-to/curl-patch-in-ruby

In Rust

/how-to/curl-patch-in-rust

In Java

/how-to/curl-patch-in-java

In Kotlin

/how-to/curl-patch-in-kotlin

Full JavaScript reference on the cURL to JavaScript hub, or open the main converter for all 18 targets.