HTTP Header Viewer

WHAT IT DOES

HTTP Header Viewer reads the current page's HTTP headers by fetching the page with GM_xmlhttpRequest and extracting request and response headers, displaying them in a structured format with sorting, filtering, and search capabilities, and allowing you to copy individual headers or the full header list. The tool provides detailed visibility into the HTTP headers exchanged between your browser and the server, helping developers debug caching issues, security headers, content negotiation, and API behavior.

WHERE IT RUNS

This tool works on any webpage, including HTTPS and HTTP sites, and handles redirects and cross-origin requests appropriately. It uses the granted GM_xmlhttpRequest permission to make HEAD requests to the current URL, capturing response headers from the server and estimating request headers from the browser context. It runs on all websites as designated in its match patterns.

HOW TO USE

After installing the BotGentz extension, open the HTTP Header Viewer panel from your browser toolbar or use the keyboard shortcut. Click "Fetch Headers" to retrieve the current page's headers. The panel displays response headers (status code, headers from the server) and estimated request headers (host, user-agent, accept, language, etc.). Toggle "Include request headers" and "Include response headers" to show or hide each section. Toggle "Show raw headers" to view the complete unformatted header list. Click any header name to copy just that header to your clipboard, or use "Copy All Headers" to export the entire list. Use "Clear Headers" to reset the display. Enable "Auto-refresh on navigation" to automatically fetch headers when you navigate to a new page.

TECHNICAL SECTION — HEADER EXTRACTION AND DISPLAY

The tool uses GM_xmlhttpRequest with the HEAD method to fetch the current page's URL without downloading the full content. This efficiently retrieves the complete response headers while minimizing bandwidth usage. The response headers are parsed from the standard HTTP header format, handling multi-line headers and duplicate header names by aggregating them into arrays. Request headers are estimated from the browser's navigator and window objects, providing useful context for debugging. The structured display presents headers sorted alphabetically for easy scanning, with color-coding to distinguish between request and response headers. Each header row is clickable for copy-to-clipboard functionality, streamlining the process of sharing header information with team members or documenting API behavior.

THE PANEL

The panel is draggable anywhere on the screen and remembers its position per site. It can snap to the left, right, top, or bottom edges, or float freely. Collapse it to a small status indicator when you need more page visibility, and expand it again with a single click. Resize it vertically or horizontally to see more header data. Press Escape to close the panel instantly. All settings (include request, include response, show raw, auto-refresh) are saved globally and persist across sessions.

PLEASE NOTE

This tool requires the free BotGentz extension. It does not collect, store, or transmit any data—all processing happens locally in your browser. The tool makes a HEAD request to the current page URL, which may be logged by the server like any other request. Some headers may not be available due to browser security restrictions (e.g., cross-origin resource policies). Request headers are estimated and may not exactly match what the browser sends. Websites change their layouts and header structures frequently; scripts may need updates, and we work to keep them current but cannot guarantee uninterrupted operation.