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About this tool
Compose a curl command with method, headers, auth, JSON or form bodies, proxies, timeouts and output options, with each flag explained.
This builder turns a described HTTP request into a working curl command line, handling method selection, headers, authentication, JSON and multipart bodies, proxies, timeouts and output redirection. Arguments are wrapped in POSIX single quotes and query values are percent-encoded, so ampersands and spaces cannot be mangled by the shell. It also flags the classic traps: -X POST alongside -d, secrets left in shell history, and -s hiding the error you needed to see.
Open Curl Command Builder on AltFTool — it loads instantly in your browser.
Paste your code or data sample into the workspace.
Pick the format, conversion, or analysis you need.
Copy the polished result straight back into your project.
Every argument is quoted, so JSON braces, ampersands and spaces survive the shell untouched.
Each option in the output is listed with what it actually does, not just what it is called.
Warns about redirects dropping the Authorization header, bodies on GET, and -k defeating TLS.
Add -H 'Content-Type: application/json' and pass the payload with -d, for example curl -H 'Content-Type: application/json' -d '{"name":"Ada"}' https://api.example.com/users. curl 7.82 and newer can shorten this to --json, which sets both the Content-Type and Accept headers.
No. Passing -d makes curl switch to POST on its own, and adding -X POST forces the method to stay POST even after a 301 or 302 redirect, which can send the body somewhere you did not intend.
With -L curl removes the Authorization header when the redirect points at a different host, as a credential-leak protection. Call the final URL directly, or add --location-trusted only if you fully trust every host in the chain.
Add -f (--fail). Without it curl exits 0 even on a 500 because the transfer itself succeeded; -f suppresses the error body and returns exit code 22 instead. Pair it with -sS so the progress meter is hidden but real errors still print.