When building great products it's essential to design and test your interfaces before actually implementing them. One way of accomplishing this is building high-fidelity prototypes that you can use to communicate your ideas or even test them on potential users.
This not only gives you valuable feedback upfront, without using any engineering costs, but also allows you to explore more and try different ideas.
What's a good process for designing the next feature in your app? What makes a good prototyping tool? How can we improve the communication between design and development?