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.

cURL to fetch / Axios: Convert Terminal Requests into Browser-Friendly JavaScript

When you already have a working curl command, rewriting it into app code by hand is tedious. A curl to fetch or curl to axios converter gives you a faster starting point: paste the command, inspect the generated JavaScript, and move from shell syntax to browser or frontend code without manually translating every flag, header, and request body.

This tool is useful when docs only show curl, when you copied a request from DevTools, or when you want to turn an API test into code you can drop into a React app or a small script. Toolzy.dev does the conversion locally in the browser, so the pasted command stays on your machine instead of being sent to a server. That matters when your request contains internal URLs, auth headers, or payload samples.

The important caveat is honesty: a curl command to fetch conversion is not magic. curl runs in a terminal with capabilities the browser does not have. Generated output may need edits for CORS, cookies, forbidden headers, unsupported flags, or environment-specific authentication. Shell prompts and line continuations are normalized, and quoted multiline request bodies stay together with line breaks preserved in the generated request string. Treat the result as a useful draft, not a guaranteed one-click migration.

What gets converted well

Most converters can reliably map the common parts of a request:

URL and query string
HTTP method like GET, POST, PUT, or DELETE
Request headers such as Content-Type: application/json
Request bodies from --data, --data-raw, or similar flags, including quoted multiline payloads that need newline-preserving string output
Basic auth or bearer-token patterns when they are explicit in the command

A simple input like curl https://api.example.com/users -H "Accept: application/json" usually becomes a clean fetch() call or an Axios config object with minimal cleanup.

Using it

Paste your full curl command into the input. Choose whether you want fetch or Axios output, generate the result, then read the generated code before copying it into your project.

If the original command includes JSON, confirm the generated body still matches what you expect. If it includes auth, confirm secrets are being handled the way your app actually handles them. For example, a copied header like Authorization: Bearer ... may need to become Authorization: + tokenFromState rather than a hard-coded string.

Browser limits you need to know before you paste

This is where many convert curl to javascript tools become misleading if they do not explain the runtime difference clearly.

curl can set low-level headers and make requests directly from your machine. Browser code cannot do that. A generated fetch() request may fail even if the original curl succeeds, because the browser enforces rules around CORS, credentials, mixed content, and restricted headers.

Common examples:

Host, Content-Length, Origin, and some other headers are controlled by the browser and cannot be set manually
Session cookies from your terminal or copied request may not be available in the browser context
Cross-origin APIs may reject browser requests unless the server sends the right CORS headers
Self-signed certificates or local networking behavior that worked in curl may behave differently in a browser

That is why a curl to fetch result should be reviewed in context, especially if the original request came from a backend environment, CLI script, or local proxy chain.

Unsupported flags and partial conversions

Not every curl feature maps cleanly into frontend JavaScript. Flags related to TLS, proxy configuration, redirects, retries, compressed transfer behavior, multipart edge cases, cookie jars, or output formatting often have no direct browser equivalent.

Examples that may need manual work include --proxy, --compressed, --cookie-jar, --resolve, --cert, --cacert, --form with file uploads, -d @file, --data-binary @file, -F file=@avatar.png, -T payload.bin, and advanced retry or timeout combinations. A converter can often preserve the intent, but it cannot recreate terminal networking features in the browser.

If your command is doing more than “send this method, headers, and body to this URL,” expect to edit the generated code.

fetch vs Axios output

fetch is built into modern browsers and keeps dependencies low:

await fetch("https://api.example.com/users", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ name: "Ada" }),
});

Axios adds its own response handling, interceptors, and a slightly different config shape:

await axios.post(
  "https://api.example.com/users",
  { name: "Ada" },
  {
    headers: { "Content-Type": "application/json" },
  }
);

If your app already uses Axios, generating Axios code saves cleanup. If not, fetch is usually the simpler default.

When this tool is most useful

You have API docs that only provide curl to axios or curl to fetch-style examples indirectly through shell commands
You copied a request from browser DevTools and want readable JavaScript fast
You are turning a Postman or terminal repro into frontend code for debugging
You want to compare how the same request looks in fetch() versus Axios
You need a fast draft for test fixtures, mocks, or prototype integrations

Troubleshooting

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.