MarkupKit is an open-source framework for simplifying development of native iOS and tvOS applications. It allows developers to construct user interfaces declaratively using a human-readable, HTML-like markup language, and can in most cases be used as a drop-in replacement for XIB files or storyboards. In addition to support for all system-provided view types, MarkupKit includes a set of UIView subclasses that make working with auto layout much easier. It also supports custom (i.e. application-specific) view types.