Definition of IxD: “Interaction Design (IxD) defines the structure and behavior of interactive systems. Interaction Designers strive to create meaningful relationships between people and the products and services that they use, from computers to mobile devices to appliances and beyond. Our practices are evolving with the world.”- from ixda.org
IxD designer is the people in charge of the websites/apps moving elements & interactions. If you’ve seen a cool animation on a website or app, that made you say wow or that is really cool, that’s the stuff motion designers do.
The job description of IxD designer at Google:
In an Interaction Designer role, you’ll tackle complex tasks and transform them into intuitive, accessible and easy-to-use designs for billions of people around the world-from the first-time user to the sophisticated expert. Achieving this goal requires collaboration with teams of Designers, Researchers, Engineers and Product Managers throughout the design process-from creating user flows and wireframes to building user interface mockups and prototypes. At each stage, you will anticipate what our users need, advocate for them and ensure that the final product surprises and delights them.
So in an oversimplified and user-friendly nutshell, UX Design is how a user feels about the apps, UI Design is what, where and how elements work on the apps, Information Architecture is how an app is organized, and Interaction Design is how the user and app act and react to each other.
Last but not least, the boundaries between each of these various design roles are very fluid. The IxD is quite similar to UX design in its approach as it’s part of the UX design cycle, so in some cases, these roles may have a lot of overlap.