HTTP Header Spy

HTTP Header Spy enables you to inspect request- response headers and cookies right after page load with no extra clicks.

HTTP Header Spy is available to install from Firefox Browser Add-ons and for download from this page. It has 318 active users The latest version is 2.0.49, and it was published 5 years ago.

Install from Firefox Browser Add-ons
View source code
Total download count: 0 (Only count downloads from Firefox-Stats)

All available versions

You can find the current and older versions of HTTP Header Spy here. You can download the archived versions or inspect their source codes.

As a free user, you can only download the latest version.

Upgrade to download older versions
Version Download Size Download count Timestamp
2.0.49 XPI · ZIP · Source code 608.70K 0 2020-01-09

Install XPI file

An XPI file, short for "XPInstall," is a compressed file format used primarily by Mozilla applications, like Firefox and Thunderbird, to distribute and install add-ons or extensions. These files are similar in function to CRX files for Chrome but cater to the Mozilla ecosystem.

  1. Simply drag-and-drop the XPI into Firefox to install the add-on.

Install ZIP file

  2. In Firefox browser, go to about:addons to open Add-ons Manager
  3. Click on , then select Install Add-on From File
  4. Select the HTTP Header Spy ZIP file from step 1. HTTP Header Spy is now installed on your browser.