Build, send and share HTTP requests from your browser
This HTTP request builder is a lightweight REST client that needs no install or account. Choose a method, enter a URL, add query parameters and headers, pick Bearer or Basic auth and a JSON, form or raw body — the equivalent cURL, fetch, axios, Python requests and HTTPie code updates as you type, so you can paste a working call into a terminal, a script or a bug report.
Press Send and the request goes out with your browser’s fetch: you see the status, the time it took, the body (JSON pretty-printed) and the response headers the server exposes. Variables such as {{baseUrl}} and {{token}} come from switchable Development, Staging and Production environments, and recent requests are kept in a history you can click to restore.
There is no proxy in the middle: requests travel directly from your device to the API, and history and variables live only in this browser’s local storage.
How to use the HTTP Request Builder
- Pick the Method and type the URL. Add extra Query parameters one per line as
key=value; they are URL-encoded for you. - Add Headers as
Name: valuelines, and choose Auth — a Bearer token oruser:passwordfor Basic. - Choose a Body type. JSON is validated as you type; form bodies take
key=valuelines. - Optionally open Environments and variables and define values such as
token=…, then use{{token}}anywhere in the request. - Copy the generated code from the cURL, fetch, axios, Python or HTTPie tab, or press Send to run the request and inspect the response.
HTTP Request Builder features
Five code targets
cURL with correct shell quoting, browser/Node fetch, axios, Python requests and HTTPie — each written idiomatically, including Basic auth, form encoding and multipart bodies.
Real sending with timing
Requests use fetch with an abort timeout. The response shows status, total time, body size, readable headers and a pretty-printed JSON body; binary bodies are summarised.
Environments and variables
Three environments with their own name=value variables; undefined {{variables}} are flagged before you send.
History
The last 25 requests are saved locally with their status and timing. Repeated requests collapse into one entry; click an entry to restore every field.
Honest error messages
When a request fails, the tool explains CORS, preflight, mixed-content, TLS and timeout causes instead of a bare “Failed to fetch”.
Why some requests work in cURL but fail in the browser
Browsers enforce the same-origin policy. A page may read a response from another domain only if that server answers with an Access-Control-Allow-Origin header that permits it. Requests with custom headers (such as Authorization) or a JSON body also trigger a preflight OPTIONS request that the server must approve. Many APIs — especially internal ones — do not send these headers, so Send fails even though the endpoint works.
This is a browser rule, not a problem with your request. The cURL, Python and HTTPie code generated here is not subject to CORS, so run it from a terminal. Public test APIs such as httpbin.org allow CORS and work with Send. The CORS tester shows which headers a server returns.
- Forbidden headers: browsers silently drop
Cookie,Host,Origin,Content-Lengthand a few others; the generated code still includes them for other environments. - Readable response headers: only CORS-safelisted headers and those listed in
Access-Control-Expose-Headersare visible to the page. - Mixed content: an
https://page cannot call anhttp://API except on localhost.
Body types and the Content-Type they send
| Body | Content-Type | cURL flag | Python requests |
|---|---|---|---|
| JSON | application/json | --data-raw | json=payload |
| Form URL-encoded | application/x-www-form-urlencoded | --data-urlencode | data=payload |
| Multipart form-data | multipart/form-data; boundary=… (set automatically) | -F | files=… |
| Raw text | text/plain unless you set one | --data-raw | data=payload |
Related tools
Already have a curl command from DevTools or documentation? Paste it into the cURL to Fetch converter. To read a long JSON response comfortably, use the JSON Formatter; to decode the bearer token you are sending, the JWT Decoder; and for the meaning of a status code, the HTTP status codes reference.
HTTP Request Builder FAQ
Is my API key sent anywhere other than the API?
No. The HTTP request builder has no server of its own: Send calls the URL you entered directly from your browser. Variables and history are stored only in this browser’s local storage — use Clear history, or avoid saving production secrets on shared computers.
Why does Send say the request failed when cURL works?
Almost always CORS: the API did not allow requests from this page. Browsers do not reveal the exact reason to scripts, but the DevTools console shows it. Run the generated cURL or Python code instead, or enable CORS on your own API.
Can I send cookies with the request?
Requests are sent with credentials: "omit", so the browser does not attach cookies from other sites, and the Cookie header cannot be set by a page. Use an Authorization header or the generated terminal code for cookie-based APIs.
How do variables work?
Write {{name}} in the URL, query, headers, credentials or body. The value comes from the selected environment’s name=value lines. Unknown variables are left as written and listed in a warning.
Can I upload a file?
Not from this page — multipart bodies here contain text fields only. The generated cURL uses -F, so you can change a value to @path/to/file and run it in a terminal.
Does the tool follow redirects?
Yes, fetch follows redirects automatically and the response line notes when one happened. The generated cURL does not add -L; add it if you want curl to follow them too.