Reveal URLs — Privacy Policy
Last updated: 2026-07-15

Reveal URLs reveals the URL each link in your mail points to so you can spot phishing before you click. It comes in three forms: the browser extension (and Thunderbird add-on), the Outlook add-in and the Gmail add-on.

The short version

Reveal URLs sends nothing to us or to any third party. There is no analytics and no tracking, and we, the developers, receive none of your data. The browser extension and the Thunderbird add-on do all their work on your own device, transmitting nothing. The Outlook add-in analyses the message on your own device and sends no email or message data anywhere; its task-pane code (HTML, JavaScript, CSS and icons) is, however, loaded from https://www.reveal-urls.eu over HTTPS (like opening any web page), so the host serving that code sees the request for it. The Gmail add-on is the one form that runs elsewhere: because Gmail add-ons run on Google's own servers, the open message is read and analysed there (by Google, who already hold your mail), never by us and never by anyone else.

What it accesses

To reveal and check links, Reveal URLs reads the visible text and the destination (href) of links in the message you're reading. How and where depends on the form:

• Browser extension: reads only within the page you're viewing, as it renders, plus the page's colours (to keep the revealed URL legible); never stored, never transmitted. The Thunderbird add-on works the same way on the rendered message.
• Outlook add-in: the task pane reads the message content Outlook provides to
  the add-in for the item you have open through Outlook's add-in interface and
  analyses it locally on your device; no email or message data is sent anywhere.
  The task pane's own code (HTML, JavaScript, CSS and icons) is loaded from
  https://www.reveal-urls.eu over HTTPS (as happens when you open any web page),
  so the host serving that code sees the request for it, not your message
  content.
• Gmail add-on: when you open a message, Google runs the add-on on its own servers, where it reads and analyses that one message under a single narrow permission and returns a card of findings. The content is processed each time you open a message and is not retained; nothing is shared with any third party.

What it stores

Only your own settings — never email or message content or browsing history.
Where they are stored or read depends on the form:

• Browser extension: enabled/disabled, display mode, colours and font sizes, your ignore-list, and any sites you add, saved via your browser's extension storage (synced across your signed-in devices by your browser vendor if sync is on; never sent to us).
• Outlook add-in: the add-in reads your optional display settings (an
  ignore-list and a mismatch-highlighting choice) from Outlook's per-user
  roaming settings when present; it stores no data of its own and never stores
  email content.
• Gmail add-on: your per-user settings, in Google's per-user properties for the add-on.

Removing the extension or add-on clears its settings.

What it does NOT do

• It does not collect, sell, or share any personal data.
• It does not send your email, link data, or browsing history to us or to any third party.
• It does not retain message content: the Gmail add-on processes each message only as you open it.
• It contains no analytics, telemetry, advertising, or trackers.
• It runs no dynamically-fetched or eval'd code; the detection logic ships bundled in each form. (The Outlook task pane's static bundle is loaded from https://www.reveal-urls.eu over HTTPS like any web page.)

Permissions

• Browser extension: storage (save your settings); access to your webmail site(s), namely FastMail, Gmail, Outlook Live, Outlook 365, Proton, Tuta, Yahoo, Zoho by default, plus any site you explicitly add and grant; scripting (run the link-revealing code on those sites); (Thunderbird) messagesRead.
• Outlook add-in: read the message content Outlook provides to the add-in
  for the item you have open (Outlook's ReadItem) so the task pane can check
  its links on your device; no email or message data is sent anywhere, and the
  task pane's own code is loaded from https://www.reveal-urls.eu over HTTPS like
  any web page.
• Gmail add-on: two permissions, namely the standard permission to run as a Gmail add-on (gmail.addons.execute), which grants no access to your mail or data, and the only data permission, to read just the message you currently have open (gmail.addons.current.message.readonly), which cannot read your other mail, send mail, or change anything.