cURL Command Builder

Enter an HTTP method, URL, headers and request body, and this tool builds a ready-to-run curlcommand for you. You no longer need to memorise quote escaping or the order of -X,-H and --data options — the command updates as you type, ready to copy straight into your terminal.

It is handy for debugging APIs, testing REST endpoints, or attaching a reproducible request to docs and issues. Everything runs entirely in your browser, so the URL, tokens and body you enter are never sent to any server — you can safely build requests that include authentication headers.

How the command is assembled

The tool composes your input in the following order. For readability each option is split onto its own line with a trailing backslash (\), but the command works identically pasted as a single line.

• Method: added as -X POST whenever it is not GET.
• URL: wrapped in single quotes to stop the shell from interpreting special characters.
• Headers: each key/value pair becomes -H 'Content-Type: application/json'.
• Body: appended via --data when the method is not GET/HEAD and the body is non-empty.

Quoting and escaping

In a shell, text inside single quotes is passed through literally with no variable substitution or escaping, which makes it the safest wrapper. The catch is that a single quote inside the value would terminate the string, so this tool converts each inner single quote into the '\'' pattern to embed the quote safely. Values full of double quotes, such as JSON bodies, can be pasted as-is.

Practical tips

1. For authenticated APIs, add an Authorization header row in the form Bearer <token>.
2. When sending JSON, also add a Content-Type: application/json header so the server parses it correctly.
3. To inspect only response headers, switch the method to HEAD and the body field disappears automatically.

Going the other way, when you need to dissect a long command someone sent you, the cURL command parser breaks the method, URL, headers and body back out into tables.

Handy curl flags quick reference

This tool emits -X, -H and --data only, but real debugging usually means tacking on a few more flags by hand. Append any of these to the end of the generated command.

A worked example

Enter method POST, URL https://api.example.com/v1/login, header Content-Type: application/json and body {"id":"alice","pw":"p'wd"}, and the tool produces:

curl -X POST 'https://api.example.com/v1/login' \
  -H 'Content-Type: application/json' \
  --data '{"id":"alice","pw":"p'\''wd"}'

Notice how the single quote inside the password (p'wd) became p'\''wd. That is three pieces — close the current string ('), an escaped quote (\'), then reopen the string (') — which the shell concatenates into one word, leaving a single literal quote inside the value.

Common pitfall

• Sending a JSON body but forgetting the Content-Type: application/json header: curl defaults to application/x-www-form-urlencoded, and many servers respond with 400.
• --data (alias -d) strips newlines from the body. To send newlines verbatim, switch to --data-binary by hand.
• A query string containing & pasted without quotes makes the shell run the command in the background — which is exactly why this tool always wraps the URL in single quotes.