The 3-year-old company now has 10,000 hotel partners in more than 400 destinations in 27 countries, compared with only 100 destinations in 12 countries one year ago. HotelTonight has logged more than 10 million downloads of its free app, which is available on iOS, Android and Windows devices.
The company has raised more than $80 million in funding through partners including Coatue Management, U.S. Venture Partners, Battery Ventures and others.
Read MoreFigure It Out When You Get There, Says Hotel Booking App
A few independent hotels have already enabled the HotelTonight express check-in feature, but Shank declined to identify them by name.
"They're in the alpha stage of this as well," he said.
The feature lets customers check in to their room with just two taps on the app, which notifies them when the room is ready. For now, they'll still need to pick up the keys.
The keyless entry option on the app still requires buy-in from individual hotels, which will need to install hardware in their doors to work with the HotelTonight app, Shank said. The keyless entry function in the app was created by Brivo Labs.
Read MoreHipmunk redesigns for younger travelers