Top Interaction Design Companies
Interaction design decides what an interface does, not only how it looks: what happens on a tap, a swipe or a failed form submission, how a menu opens, how long a transition lasts and what feedback tells a user that an action worked. Interaction designers specify states, gestures, micro-interactions and motion so a product feels responsive and predictable. Product companies hire them for apps with complex input such as trading, scheduling or medical devices, for game and kiosk interfaces, or when a product works on paper but feels clumsy in use.
When comparing studios here, ask for prototypes that show behavior in motion, and check whether they deliver motion specs engineers can implement, not only video.