This article acts as a very brief overview on tvOS apps and provides some further reading links. If you are looking to build out your first tvApp this article is a good starting spot.
2 Ways of Building tvOS Apps
From a developer's point of view its important to introduce the 2 ways in which we can build out our tvOS apps, Apple have presented us with 2 ways to develop tvOS apps.
Those familiar with iOS workspaces will be well on their way picking up the custom apps way of working. Writing native code and making use of many ui elements which can also be found in UIKit.
What are TVML, TVJS, TVMLKit?
With the introduction of tvOS, Apple have introduced a few new anocryms to break up the technologies used to create tvOS apps.
TVML is the abbreviation of Apple’s Television Markup Language. In its most basic form it is a form of XML that is used to create individual views inside of a client-server app. TVML is the setting stone of the templates developers are able to use to layout their views within their tvOS apps.
It would be fair to say that the TVML route of development is aimed more at beginners or those wishing to creating more intuitive/ familiar apps. Making use of the common tvOS views seen in Apple's own apps. For example if the purpose of your project is to build out a video catalogue of your content using Apple's guidelines - TVML is perfect as it provides an easier, faster way to build out tvOS apps with the common features and UI components.
Those looking to add more advanced features (e.g. custom/ advanced UI, analytics, crash reporting) would be better suited to custom builds. Through personal experience this may be more beneficial to larger clients who may wish to customise and extend the experience as their user base grows.
For those looking to build their first tvOS apps - here are some great articles...