Right after you book on Booking.com, Expedia, Hotels.com or Agoda, Underbook can offer, once, to watch that booking, with the hotel, dates, price and free-cancellation date filled in from the confirmation page for you to check. Nothing about the booking is sent unless you type your email and press the button. It then checks once a day until free cancellation ends, emails you once if a listed rate is at least 5% lower on two daily checks in a row, and reminds you a week before and the day before free cancellation ends. When another site lists free cancellation for the same price or less, the banner now says so. The "−" button shrinks the banner to one line, and changing dates on the page checks again at once.

The toolbar icon now shows "ON" on booking sites Underbook reads and a mark when a check is done. A small tip on a booking site's home or search page says Underbook works there (at most once a day, once every 14 days per site, with a "Don't show tips again" button). Better results for travelers outside the US: Expedia's German, French, Italian, Spanish and Dutch hotel pages are recognized, the hotel's town is read correctly, and prices are labeled with the country they were quoted for. The banner now says plainly that Underbook may earn a commission if you book through its links.

Better hotel detection: Agoda stays checking in on days 1 to 9 of a month now get a comparison; Booking.com keeps your dates after an old link redirects; Trip.com and IHG (including Kimpton) hotels are recognized; your page's currency and a 1-adult party are used; hotel names like "The Ritz-Carlton, Chicago" keep their town.

What's new since 0.5.25:
- Works on more booking sites and hotel websites: Hotwire, Orbitz, Travelocity, Wotif, ebookers, CheapTickets, Priceline, KAYAK hotel pages, Hilton, IHG, Hyatt, Choice, Wyndham, Accor, Radisson and Best Western.
- One line of room evidence on a lower price: both room names when they match, or a plain note when the cheaper site names no room. Check the room before you book.
- "I already booked this stay": enter what you paid and your free-cancellation date, and get one email if a listed rate is at least 5% lower on two daily checks in a row.
- Share this check: copy a link that reruns the same price check on underbook.co.
- The first hotel page you open is checked right away.
- Clearer banner: one main button per card, readable text, nothing cut off on small windows.