A great tool for high-fidelity prototypes, especially for user testing. It makes your prototype look and feel like a real app: https://www.flinto.com/:
Flinto
Visual representation of Flinto
Get Fixing Bad UX Designs now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.