Help. Updated October 3, 2026
Underbook help center
Short answers about the Underbook browser extension and the web price checker. Each answer starts with the short version, then gives the detail and links to the page that goes deeper.
Which version do I have? The Chrome Web Store, Microsoft Edge Add-ons and Firefox Add-ons each review a new version of Underbook before they serve it, each on its own schedule, so for a while Chrome, Edge and Firefox can run different versions. Your browser updates Underbook by itself once its store serves a new one. Where an answer depends on the version, it says from which version; your browser's extensions page shows yours (Details in Chrome and Edge, about:addons in Firefox).
Getting started
What it does, where it works, pinning the icon, and phones.
Prices and rooms
Where prices come from, same room name, all-in, why prices differ, and the free-cancellation note.
- Where do Underbook's prices come from?
- What does "same room name" mean, and what does it not mean?
- What does "all-in" mean, and when is a price a "listed rate"?
- Why is the price different from what the booking site shows me?
- What is the "going rate"?
- What does "Free cancellation for the same price" or "for less" mean on the banner?
Price alerts and watching a booking
Emails when a stay gets cheaper, watching a booked stay from its confirmation page, reminders before free cancellation ends, and stopping them.
Privacy and data
What a check sends, what stays on your device, and deletion.
Money and trust
Commissions, what the extension can access, and lower prices that disappear.
Troubleshooting by browser
Settings to check in Chrome, Edge and Firefox, and removing it.
Not answered here?
Write to hi@underbook.co. Questions, requests to delete your data and reports of something wrong all go there.
The longer explanations: how Underbook works, and how to check us, the privacy policy and the corrections log. No extension? The web price checker runs the same comparison on any phone or computer.