Extension name: NERD IP info

Last updated: July 1, 2026


This extension stores the following information locally in your browser:

• Your NERD API key, which is used to authenticate requests to the CESNET NERD service.
• A history of IP addresses you have queried, to provide convenience features such as query history.
• Cached reputation data — reputation scores and state for IP addresses you have looked up or scanned, cached locally to avoid repeated API requests and to color-code IP icons on pages.
• Tag and blacklist name maps — metadata downloaded from the NERD service and cached locally to translate numeric IDs into human-readable names.
• Extension settings — your preferences, including whether IP detection is enabled and the indicator style
• Site allowlist/blocklist — hostname or URL patterns you enter to control on which sites IP detection runs.
• Pending lookup — a temporary entry used when you open the popup via the right-click context menu.

The stored information is used solely to provide the functionality of the extension:

• The API key is used only to authenticate your requests to the NERD service.
• Queried IP addresses are stored only to maintain your local query history.
• Page content is scanned only to detect and highlight IPv4 addresses according to your settings.
• Site allowlist/blocklist patterns are used only to decide whether to run IP detection on a given site.
• Cached maps are used only to render readable tag and blacklist names in the popup.

All data is stored locally in your browser

The extension does not collect, transmit, or share your API key, query history, cached reputation data, settings, site lists,or any other personal information with the developer or any third party.


When you perform a lookup, the extension sends the queried IP address and your API key directly to the CESNET NERD (Network Entity Reputation Database, https://nerd.cesnet.cz/) service in order to retrieve reputation information. This communication occurs only when you explicitly initiate a lookup.

The extension also periodically downloads tag and blacklist metadata from the NERD service so it can display human-readable names. These requests include your API key for authentication and occur automatically when the cached maps are stale or missing.

Apart from requests required to communicate with the NERD service, the extension does not transmit any data outside your browser.


All data remains in your browser's local extension storage until you clear it or uninstall the extension. Uninstalling the extension removes the stored data from your browser.


This Privacy Policy may be updated from time to time. Any changes will be reflected by updating the "Last updated" date at the top of this document.


If you have any questions about this Privacy Policy, please contact the developer directly at nerd@cesnet.cz.