Privacy and data

For each check, the extension sends Underbook's price service the hotel's name, your check-in and check-out dates, the number of adults, the booking site's market and currency and the extension's version, plus the hotel's town when the page shows it (from version 0.5.30), and nothing that identifies you.

• Usage statistics: anonymous events such as "a comparison was shown", with a random install id made on your device, the type of result, the days since install and, in the newest version (from 0.5.33), once a day whether the icon is pinned. They are counted as daily totals and never carry a web address, a hotel name, your dates or your email. In Firefox they are sent only if you allow technical and interaction data.
• Only if you set a price watch: your email and the stay; for a stay you already booked, also the price you paid per night, its currency, your free-cancellation date and the name of the site you booked on.
• Never: your payment details, your browsing history or the other pages you visit.

On your device only, the extension keeps the last 25 stays you checked (so a return visit can say what the price did), your email if you set a watch, and a few small counters and settings. They are removed with the extension.

No: on a page that is not a hotel page the extension sends nothing about that page, not its address, its title or its content.

From such pages it sends only an anonymous once-a-day usage ping and, on a booking site it reads, an anonymous count when it shows a small tip there (the event name only: no address, site or search). To find hotel pages it reads, inside your browser, a page's title, metadata and date fields. That is why your browser says it can read and change data on the websites you visit: hotel pages are on hundreds of booking sites and hotels' own websites.

When you click its toolbar icon, you ask it to check that page: it reads the page's title or main heading as a possible hotel name and sends that name and any dates it finds, like any check. It uses no cookies and no tracking pixels.

Write to hi@underbook.co and we will delete your email and the watches it is attached to; the rest needs nothing from you, because Underbook has no accounts and stores your email only for a watch you set.

• A watch: Unsubscribe in any of its emails stops it and deletes it. A watch on a booked stay is also deleted automatically the day after check-out.
• On your device: removing the extension removes everything it stored there.
• Usage statistics: kept only as anonymous daily totals. The install id is not stored on Underbook's servers and no IP address is kept, so nothing there is tied to you.
• Lookups that found no price go in a short list (the most recent 50, kept at most 30 days) that records the hotel and dates but nothing about who asked.
• An email you left in the homepage's old waitlist or watch forms: ask at the same address.