⌘ K
curl → fetch() · headers · body · JSON-aware · live

Convert cURL to fetch()

Paste a cURL command and get an idiomatic JavaScript fetch() call — method, headers, query and body all wired up. Runs entirely in your browser.

cURL → fetch()
Input
161 B
4 lines
Output
263 B
9 lines
Status
ready
live
Ratio
1.63×
out/in
input · curl command
output · javascript
const res = await fetch("https://api.example.com/users", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "Authorization": "Bearer abc123"
  },
  body: JSON.stringify({"name":"Alice","role":"admin"}),
});
const data = await res.json();
Quick Start

How to convert cURL to fetch()

The parser walks your cURL flags, normalises -X / -H / -d / -u into a JavaScript options object, then renders a copy-ready fetch() invocation.

  1. 01

    Paste cURL

    Drop in a cURL command from browser DevTools (Copy as cURL), Postman’s code snippet panel, a shell tutorial, or a bug report. Multi-line continuations with \ are handled automatically.

    The parser recognises -X, -H, -d, --data, --data-raw, -u, and quoted URLs — the bits 90% of real-world calls use.

    DevToolsPostmanmulti-line-X · -H · -d
    input · curlloaded
    curl -X POST https://api.example.com/users \
  -H "Authorization: Bearer abc"
    67 B · 2 linesready
  2. 02

    Headers and body wire up

    Each -H flag collapses into a Headers-style object on RequestInit. The body becomes JSON.stringify(...) when --data looks like JSON, otherwise it falls back to a template literal so non-JSON payloads survive verbatim.

    Method defaults to GET, flips to POST automatically when a body is present (mirroring real cURL behaviour), and uses your explicit -X when set.

    fetch APIRequestInitHeadersJSON.stringify
    config · optionsfetch-ready
    { method: "POST",
  headers: { Authorization: "Bearer abc" },
  body: JSON.stringify({ name: "Alice" }) }
    wiredidiomatic
  3. 03

    Drop into modern code

    The output reads like a hand-written async/await fetch — paste into a Next.js route handler, a React Query queryFn, a service worker, or a Cloudflare Worker. The snippet is plain ESM JavaScript, no transpile required.

    For top-level await use a route handler or module with type: "module"; otherwise wrap in an async function.

    async/awaitESMfetchNext.js
    run · asyncawait · ready
    const res = await fetch(url, opts);
const data = await res.json();
    runnablemodern
  4. 04

    Copy or download

    Copy the snippet to your clipboard, or download as a .js file. The parser, mapper, and renderer all run locally — your cURL (often loaded with bearer tokens) never leaves the browser.

    Open DevTools → Network to verify: zero outbound requests.

    clipboard.jsESMprivacy-first
    export · fetch.jsready
    ✓ Copied to clipboard
✓ Saved: fetch-call.js
✓ 100% client-side
    ready to shipsuccess
Pro tips

Converting between formats, safely

Pick the strictest source format

Lossy formats hide bugs. Choose JSON or YAML as your source-of-truth, convert downstream as needed.

Round-trip in CI

If your converter is idempotent, your CI can verify A → B → A equals the original. Catches subtle data loss.

Numbers vs strings differ

YAML/TOML have a number type; CSV doesn’t. Quote IDs in CSV to keep leading-zero values intact.

Watch character encoding

Source format may be Latin-1 / Windows-1252; target should be UTF-8. Convert encoding before structure.

Preserve comments where you can

YAML and TOML support comments. Don’t silently drop them — they often encode intent.

Schema-aware beats blind

Use a schema to guide conversion. Field types, required-ness, and defaults survive better with structure.

Related toolscURL to CodecURL to PythoncURL to axioscURL to GoHAR to cURLcURL to Rust
Use Cases

When to convert cURL

DevTools replay, docs samples, edge-function debugging.

Copy as cURL

Drop a DevTools Copy-as-cURL into your front-end as fetch(). Type information survives: numbers stay numeric, booleans stay boolean, strings stay strings. The destination parser doesn't have to re-coerce, which avoids the "'true' becomes "true"" bug class.

round-trip safe

API docs

Pair raw cURL with idiomatic JS in your README. Run output back through the inverse converter to verify idempotent round-trips in CI. A → B → A should produce byte-identical input — if it doesn't, you've found data loss.

type-preserving

Edge functions

Convert backend cURL examples to runnable Workers code. Comments and metadata survive where the target format supports them (YAML, TOML, HCL). The tool doesn't silently drop intent-encoded annotations, which keeps your config self-documenting.

schema-aware

Front-end auth

Translate Postman calls into a fetch() with bearer headers. Pair with a schema (JSON Schema, OpenAPI, Zod, Pydantic) to catch shape drift on either side. Catch breaking changes at conversion time rather than at runtime in production.

lossless

Quick repros

Reproduce a bug report's cURL inside the affected app. Output respects target-format conventions: quoting in CSV, indent in YAML, brackets in JSON. Existing parsers don't need patches, and the result drops into legacy pipelines unchanged.

diff-clean

Teach modern fetch

Show juniors how a cURL maps to async fetch + json(). Encoding-aware: handles UTF-8 vs UTF-16 vs Latin-1 / Windows-1252 transparently. The character-set surprise that breaks "works on my machine" doesn't apply here.

spec-grade
FAQ

Frequently asked questions

Yes — when --data starts with { it wraps the value in JSON.stringify(); otherwise it falls back to a template literal.
Basic auth (-u user:pass) lands in the headers via the underlying parser; cookies need manual handling because fetch() doesn't include them by default.
Not automatically — add it manually when you want cookies sent cross-origin.
Yes inside an async function or top-level await. Surround with try/catch in production.
No. Parsing and emission run locally in your browser.
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