Underbook — check for a cheaper hotel rate
On any hotel page, Underbook finds a lower all-in rate (taxes incl.) on other sites, shows the room, and can email you if it drops.
As of June 2026, Underbook — check for a cheaper hotel rate has — users in the Shopping category.
Usersno change0%
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Ratingno change0%
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— reviews
Reviewsno change0%
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Version
0.4.0
Manifest V3
90-day change · In the last 90 days this extension 1 version update, changed permissions.
History
2 snapshotsTracking since Jun 4, 2026.
Not enough history yet for this metric — the chart fills in as we collect more snapshots.
View as table
| Date | Users | Rating | Reviews | Version |
|---|---|---|---|---|
| Jun 4, 2026 | — | — | — | 0.1.0 |
| Jun 9, 2026 | — | — | — | 0.1.0 |
| Now | — | — | — | 0.4.0 |
Changelog
- Jun 9, 2026short_description
On Booking, Expedia & Hotels.com, Underbook checks other sites for a lower rate and shows the room & terms to compare.
On any hotel page, Underbook finds a lower all-in rate (taxes incl.) on other sites, shows the room, and can email you if it drops.
- Jun 9, 2026host_permissions
https://www.booking.com/*, https://www.expedia.com/*, https://www.hotels.com/*, https://www.google.com/travel/*
https://underbook-backend.underbook.workers.dev/*
- Jun 9, 2026permissions
scripting, storage
storage, activeTab, scripting
Permissions & access
- Permissions
- storageactiveTabscripting
- Host access
- https://underbook-backend.underbook.workers.dev/*
Screenshots
About
Underbook double-checks the hotel you're already shopping for. When you're on a hotel page at Booking.com, Expedia, or Hotels.com, Underbook quietly checks other booking sites for the same stay and tells you if there's a lower listed rate — without you leaving the page. HONEST BY DESIGN We don't pretend an unfamiliar rate is the exact same room. When we can't confirm the room type and cancellation terms match, we say so plainly and show you both, side by side, so you can decide. No fake guarantees, no invented savings. HOW IT WORKS 1. Shop hotels like you always do — nothing to change. 2. In the background, Underbook checks other booking sites for the same dates. 3. If it's cheaper, we show the room and cancellation terms to compare. You always book on the site you choose. PRIVATE BY DEFAULT • The check runs in your own browser — there's no Underbook server collecting your activity. • We never see, store, or transmit your payment details. • We don't sell your data. There's nothing collected to sell. WHAT UNDERBOOK IS NOT We don't book for you and we never hold your card. We surface a lower listed rate and the details you need to verify it — the decision and the booking stay with you. Free during early access. Questions: [email protected] · Privacy: https://underbook.co/privacy
Technical
- Version
- 0.4.0
- Manifest
- V3
- Size
- 17.16KiB
- Min Chrome
- 88
- Languages
- 1
- Featured
- No
Metadata
- ID
- bfkhcloifkimjimedcijpenafnkfibid
- Developer ID
- u53c913206696e86cbf9b2e55296a5cfa
- Developer Email
- [email protected]
- Created
- Jun 3, 2026
- Last Updated (Store)
- Jun 5, 2026
- Last Scraped
- Jun 9, 2026
- Website
- —
- Support URL
- https://underbook.co
- Privacy Policy
- https://underbook.co/privacy
Data sourced from the Chrome Web Store · last verified Jun 9, 2026.