How to Convert cURL Commands to JavaScript, Python & Go

Every client library spells the same HTTP request differently. A curl one-liner that sends a POST with one header and a JSON body becomes five different snippets depending on whether you're writing fetch, axios, Python requests, Go or C#. Converting by hand means keeping every -H, -d and --cookie straight — which is exactly where subtle bugs slip in.

curl flag

The command-line switch that describes a request part: -X sets the method, -H a header, -d the body, -u basic auth, -F a multipart form field.

URL-encoded body

A request body of key=value pairs joined by &, the format HTML forms and some APIs use instead of JSON.

Multipart form (multipart/form-data)

An upload format that separates fields and files with boundaries — produced on the command line with -F 'field=@file'.

Cookies

Small state tokens sent back to the server; in curl they're attached with --cookie or --Cookie, and in client code they must be re-sent on every relevant request.

What the importer has to read

• The method — from an explicit -X POST or inferred from -d.
• Every header, including duplicate headers and quoted values with spaces.
• The body — raw JSON, URL-encoded pairs, binary data with --data-binary, or multipart uploads.
• Authentication — -u user:pass becomes basic-auth headers; --cookie attaches session state.
• The URL, with its query string intact.

A command, tokenized

curl -X POST 'https://api.example.com/orders?dryRun=true' \
  -H 'Content-Type: application/json' \
  -d '{"qty": 2}'

const response = await fetch(
  "https://api.example.com/orders?dryRun=true",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: '{"qty": 2}',
  }
);

When actually sending beats converting

If the goal is to check whether the request works at all, send it before you translate it. The API Tester accepts the request, runs it live and shows the status and body — so you verify behavior first and generate code from a request you already know is valid. Convert last, and only then does the importer's output become the code you ship.

From one command to a whole documented API

A single curl command only describes one call. When the endpoint is part of a larger contract, the OpenAPI workbench generates code from every operation in the specification — paths, parameters, request and response schemas — so you're not pasting one command at a time.