Not only does Booking.com offer a perfectly optimized mobile site, but they also have one of the best travel apps on the market. For a completely streamlined experience with a remarkably smooth mobile interface, Booking.com’s mobile app is the perfect companion to your travel plans. Available on both Android and iOS devices, the Booking.com app is definitely worth a download (it is free, after all). Add it to your travel app folder and pull it up any time you need to plan a trip, or any time that you are fantasizing about your next trip, shopping around to see where you might go and where you might stay once the window of opportunity opens itself up next. With a 4.8 star rating (out of 5) on the Apple App Store, I think the quality of the Booking.com app speaks for itself.