Build and test HTTP requests with method, headers, body, and authentication options using the Fetch API.
HTTP Request Builder turns a target URL, HTTP method, headers, optional authentication, and body into a request sent through the browser's Fetch API. It is useful for checking how an endpoint responds without first writing application code. The common surprise is that this is still a browser request: cross-origin policy, mixed-content rules, and browser-controlled headers apply. A request that succeeds in curl or server-side code can therefore fail here even when its URL, credentials, and payload are otherwise correct.
Enter the endpoint and select its method, then add the headers, authentication values, and payload required by that endpoint. The body and Content-Type header are separate parts of the request. Declaring application/json does not repair or convert malformed JSON. Fetch requests using GET or HEAD cannot carry a body, so payload testing requires a method that permits one.
Testing sends the configured request from the current browser context. The builder itself does not upload the configuration to the site's backend, but sending necessarily transmits the selected headers, credentials, and body to the target endpoint. The readable result is limited to what that endpoint returns and what the browser permits the page to access.
The builder sends through Fetch in a web page, while curl is not governed by browser cross-origin policy. The endpoint may omit the CORS response headers needed for the page to read its response, reject an OPTIONS preflight, or be blocked as insecure mixed content. A curl success therefore does not guarantee a browser-visible success.
No. It is appropriate for requests that a browser is allowed to issue and inspect. It cannot reproduce every low-level header, bypass CORS, or perfectly model a backend network environment. Avoid placing long-lived production secrets in browser tooling; any credential included in a sent request is delivered to the target URL.
The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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