Hello @Travanti and welcome to the Help forums. The Blaze isn't a smartwatch, so you can't add apps to it from the App Gallery. There are apps that are compatible with the Fitbit app and you can sync those accounts. You can see that page here.
Laurie | Maryland
Sense 2, Luxe, Aria 2 | iOS | Mac OS
Take a look at the Fitbit help site for further assistance and information.
Best AnswerActually @LZeeW, the Blaze was considered Fitbits first attempt at a smart watch. But it had a proprietary operating system that 3rd parties couldn't access. It was limited to what programs Fitbit made for it.
Best Answer