The generated code runs in `curl` but fails in the browser

That usually means a browser-only restriction such as CORS, blocked cookies, mixed-content rules, or forbidden headers. The terminal and the browser do not have the same networking model.

Some `curl` flags were ignored or simplified

That's expected for flags that do not map cleanly to browser JavaScript, such as proxy, TLS, cookie jar, retry, or low-level transfer options. Review the output and re-implement those parts manually if needed.

I used a file-backed payload flag

Commands like `-d @file`, `--data-binary @file`, `-F file=@avatar.png`, or `-T payload.bin` depend on local disk access. The browser cannot read those files for you, so the converter warns and you will need to inline or otherwise rebuild the payload yourself.

My quoted multiline body changed

Quoted multiline payloads stay together and preserve line breaks in the generated request string, often via `\n` escapes. Unquoted line breaks and shell prompt markers are still normalized before parsing, so review shell-dependent input carefully.

The converter kept headers that my app should not send

Remove copied request headers like `Host`, `Content-Length`, or browser-generated `sec-` headers. They are often invalid or unnecessary in handwritten `fetch` or Axios code.

Cookies or auth do not behave like the original command

A browser request does not automatically inherit terminal cookies, local cookie jars, or backend credentials. You may need `credentials: "include"`, a different auth flow, or server-side code instead.

Can I trust the generated JavaScript without reviewing it?

No. A `curl to javascript` conversion is a starting point. Check the URL, method, headers, body encoding, and runtime constraints before shipping it.

Is the request uploaded anywhere?

No. On Toolzy.dev, the conversion runs in the browser, so the pasted `curl` command stays local to your machine.

cURL to fetch / Axios

Convert pasted curl commands into fetch or axios code without leaving the browser.

cURL input

Ctrl/Cmd+Enter

Generated fetch code

Browser fetch code with converter warnings when relevant

Browser-first output

fetch output targets browser APIs. CORS, forbidden headers, proxy settings, and low-level TLS options still depend on the runtime.

Unsupported curl features

Flags that read local files, write downloads, use cookie jars, or depend on shell behavior may convert partially or surface warnings instead of exact equivalents.

Axios target

Axios output is useful when your app already depends on axios, but it still needs your project's import, auth, and error handling conventions.