Starwood Hotels & Resorts, the operator of hotel chains such as W Hotels and Westin, is rolling out an app for using your mobile phone to unlock your hotel room, available across all of its chains in the next couple of weeks.

The app lets you unlock your room by holding your phone in front of your door, allowing you to bypass the front desk entirely if you have a reservation. That function could soon make the Starwood mobile app indispensable to mobile travelers. And that, in turn, is motivating Starwood to come up with other mobile app ideas to improve engagement with the brand.

“Keyless has been a game changer for us,” said Julie Atkinson, senior vice president of digital at Starwood Hotels & Resorts worldwide, in a talk with VentureBeat’s Nadine Dietz at our MobileBeat 2015 conference. “Technology is changing the way our guests travel, far beyond the booking process.”

Starwood has adopted “state aware” technology, so that it knows where you are when it is sending you a promotion. Before your stay, it can push relevant tourist sites near your hotel or a map with directions to your hotel. During your stay, Starwood can offer dining and other promotions that you can use at the hotel. And post-stay, it can send you feedback surveys, ask you to check in on social media, or offer promotions for your next trip.

Atkinson said that the use of smartphones for hotel activities is still evolving. Most users still use desktops to book long trips, but they are increasingly using their smartphones to book short, last-minute trips.

Starwood is also redesigning its apps according to the type of device it will be viewed on. The company’s iPad app is meant to deliver a “lean-back” experience, where you can shop or dream about where you want to travel next. But the smartphone app is designed for “one touch, one eye,” meaning you’re probably distracted while using the smartphone app.

“Smartphone apps are tactical and in the moment,” Atkinson said. “You can use it in an airport, and get pushed relevant content at the time you need it.”

Atkinson said 190,000 people have already registered for keyless check-in. Starwood had to redesign the keyless app after its first try. Initially, you had to show your app to the door handle, and then turn it to the right as if it were a door. Guests were confused about whether to turn the handle itself, so now Starwood just opens the door once someone holds their phone in front of it.

The company is brainstorming other apps, like a meeting planner app that lets you select a meeting room in the hotel and pre-set the temperature to the most comfortable level for you.

“It’s about knowing what a guest wants, offering them what they want, and not offering something they don’t want,” Atkinson said.

But before Starwood deploys any new apps, it will test them with its own hotel workers or “associates.”

As for what’s next, Atkinson said, “I struggle with personally doing innovation and doing the basics really well. Even in desktop. We need to be continuously evolving there as well. And we have to provide great service on the property.”