cURL to fetch Guide
cURL is perfect for quick command-line API tests. But when moving into frontend or Node.js code, converting to `fetch` saves time and avoids manual rewrite mistakes.
What it is
- cURL is a command-line tool for making HTTP requests.
- A cURL to fetch converter transforms common flags into JavaScript request code.
Why developers use it
- It accelerates the transition from terminal tests to application code.
- Headers, method, and request body stay consistent across conversion.
- It reduces manual copy/paste errors in API integration work.
Example
curl command and equivalent fetch snippet
Input
curl -X POST "https://api.example.com/users" -H "Content-Type: application/json" -d "{\"name\":\"John\"}"Output
fetch("https://api.example.com/users", {
method: "POST",
headers: {
"Content-Type": "application/json"
},
body: "{"name":"John"}"
});Common edge cases
Most converters handle basic GET/POST but fail on real-world requests:
- -u user:pass (Basic Auth) — should map to a proper Authorization header, not be silently dropped.
- -d with JSON body — should set the correct Content-Type when the payload is JSON.
- --data-urlencode — should encode params correctly in the URL.
- Multipart/form-data (-F) — requires FormData in fetch, not a raw body string.
The apidevtools converter handles all of these automatically.
curl to fetch vs curl to Axios
Both fetch and Axios are valid targets — the choice depends on your project:
| Feature | fetch | Axios |
|---|---|---|
| Built-in | Yes (browser + Node 18+) | No (requires npm install) |
| Interceptors | No | Yes |
| Auto JSON parse | No (manual) | Yes |
| Error on 4xx/5xx | No (manual check) | Yes (throws) |
Use fetch for lightweight scripts or browser extensions. Use Axios for larger apps that need interceptors, retries, or cleaner error handling.
When to convert curl to Python instead
If you're working in Python (data science, scripting, automation), convert to requests instead of fetch. The key distinctions:
- Use json= (not data=) when sending JSON — requests handles serialization.
- Use auth=('user', 'pass') for Basic Auth (-u flag).
- Response parsing: response.json() vs manual JSON.parse in JS.
How to use the tool
- Paste a curl command into the input field.
- Click Convert to generate a fetch snippet.
- Copy and paste the output into your codebase.