They have an SDK built on top of Qt Creator and it runs on OS X, Windows and Linux [1]. Linux may offer some advantages, such as access to the phone file syste

They have an SDK built on top of Qt Creator and it runs on OS X, Windows and Linux [1]. Linux may offer some advantages, such as access to the phone file system. OSX has a bit cumbersome ways to access it [2]. If you want to write programs for it, you can use Qt C++, QML or Python. It also has a terminal with the usual bash commands. And, of course, you can always write Android apps with tools given by Google and run those apps on Jolla. As a niche hardware feature, the original Jolla phone has a hackable i2c bus under its back cover. Some people have tried to build keyboards, e-ink screens etc. connected to it. The specs for the bus are public [3]. I'm not sure if the new Jolla C is really meant for casual users, because you need to participate in their community device program to get one. EDIT: removed some speculations about the community program EDIT2: looks like the original Jolla phone isn't sold anymore [1] https://sailfishos.org/wiki/Application_SDK_Installation https://sailfishos.org/wiki/Application_SDK_Installation [2] https://jolla.zendesk.com/hc/en-us/articles/201440867-How-do-I-transfer-files-between-a-Mac-and-my-Jolla- https://jolla.zendesk.com/hc/en-us/articles/201440867-How-do... [3] http://jolla.com/the-other-half-developer-kit/ http://jolla.com/the-other-half-developer-kit/