Why do I always get a request failure or CORS error?

Browsers are constrained by the same-origin policy: cross-origin requests require the target API to return appropriate CORS response headers (e.g., Access-Control-Allow-Origin). If the API does not allow cross-origin, the browser blocks the request and hides details. You can switch to calling a cross-origin-supporting API, or use it in a same-origin environment with the API.

Why can't I see some response headers?

For cross-origin responses, the browser only exposes a limited set of safe response headers by default; others must be explicitly exposed by the server using Access-Control-Expose-Headers, or scripts cannot access them. This is a browser security constraint, not a tool issue.

Does it support file uploads or sending forms?

The current version is focused on text request bodies such as JSON and plain text. You can manually set the Content-Type header and paste the content in the request body. File uploads and other complex forms are not supported yet.

HTTP Client

100% local processing

Request Headers

Frequently Asked Questions

No. Requests are sent directly from your browser to the target address you enter, data is transmitted between your device and the target API, not passing through qktools' servers, and we do not record request or response content.

What is an HTTP Client

An HTTP client is an online API debugging tool, similar to a lightweight version of Postman in the browser, used to quickly send HTTP requests and view responses to verify API behavior without installing desktop software.

Requests are sent directly to your specified target address using the browser's native fetch API, and responses are returned directly to your browser. qktools does not act as a proxy, forward, or log any request and response data.

How to Use

1Select the request method (GET, POST, PUT, PATCH, DELETE, etc.) and fill in the target API endpoint.
2Add request headers as needed, for example, Content-Type: application/json.
3For POST/PUT and other methods with a body, fill in the content to be sent in the request body (e.g., JSON).
4Click 'Send' to view the response status code, time taken, response headers, and response body; JSON responses are automatically formatted and indented.

Why Choose qktools' HTTP Client

Privacy First: Requests connect directly to the target API, so sensitive addresses, tokens, and data do not pass through our servers.

No Installation: Open the web page and use it; no client installation or registration required.

Clear Responses: Status codes are color-coded by range, JSON is automatically formatted, and response headers are readable item by item.