In the past few years, we have covered plenty of smart iPhone compatible door locks here. The Level Bolt is also worth a look. It is an invisible smart door lock that combines with your smartphone to give you painless, secure access. Level Bolt has a 6-guage stainless steel gearbox. It makes your existing lock smart, allowing you to lock/unlock your door with your phone.
Thanks to HomeKit support, you can control the Bolt with Siri. This smart lock runs for a year on a single CR2 battery. You can install it using only a screwdriver.[where to get it]