During the mobile app development cycle, User-Interface (UI) components rendered by the mobile app are typically validated against high-fidelity mockups by manually comparing screens from a mockup design to screens developed in the app. This validation most often takes the time of the lead designer, resulting in many post-sprint defects and tasks that must be folded into the next sprint iteration. To improve this process, an engineer should be able to validate layout as part of the acceptance criteria for each task submitted, providing a more complete UI, less defects and reduced cost for the app development. We propose a system of improvements for moving this process forward by automatically validating layout. The system is based on techniques from computer vision, in conjunction with style policies, which together facilitate validation of design layout prior to submitting completed task work, thereby reducing the overall cost of developing UI designs.