curl to fetch Converter

What this tool does

curl to fetch Converter parses a curl command, including its method (-X), headers (-H), request body (-d / --data) and basic auth (-u), and generates equivalent JavaScript using the fetch() API, as either an async/await function or a .then() promise chain.

API documentation and browser dev tools’ "Copy as cURL" feature both hand you a ready-to-run curl command, but turning that command into working JavaScript for a web app or Node script still means manually re-typing the URL, method, headers and body into fetch() syntax, which is easy to get subtly wrong.

This converter parses a pasted curl command directly, recognising the -X/--request method flag, -H/--header entries, -d/--data/--data-raw request bodies and -u/--user basic auth credentials, and generates the equivalent fetch() call, either as a modern async/await function or a .then() promise chain.

How to use curl to fetch Converter

1. Paste the full curl command, including any line continuations.
2. Choose whether to generate async/await code or a .then() promise chain.
3. Read the generated fetch() JavaScript.
4. Copy it into your project and adjust the response handling for your actual use case.

Tips for better results

• If a curl command includes -d or --data without an explicit -X, this tool defaults the method to POST, matching curl’s own real behaviour.
• Basic auth (-u user:pass) is converted into an Authorization: Basic header with the credentials Base64-encoded, exactly matching what curl does internally.
• The generated code always assumes a JSON response body via res.json(); adjust that to res.text() or another method if the API you’re calling returns something else.
• Multi-line curl commands copied from a browser’s "Copy as cURL" feature, with backslash line continuations, are handled directly without needing to join them into one line first.

Common use cases

• Converting an API documentation example written as a curl command into working JavaScript for a web app.
• Turning a "Copy as cURL" request copied from browser dev tools into fetch() code to reproduce the request programmatically.
• Quickly prototyping a JavaScript API call from a curl command a colleague or support engineer shared.
• Learning the mapping between curl flags and their fetch() equivalents.

Common mistakes to avoid

• Pasting a curl command with options this tool doesn’t recognise (such as file uploads with -F) and expecting them to be converted; only method, headers, data and basic auth are currently handled.
• Forgetting to adjust the response handling if the API doesn’t actually return JSON; the generated code assumes res.json() by default.
• Leaving a real bearer token or API key from a copied curl command in code that gets committed to version control; always move real secrets into environment variables first.