UI stands for user interface, which is how the design and styles are applied to the digital product. A bit simpler than UX, UI determines all of the styles that will be used in the product, from the H1 font to the button border width, while also taking into consideration responsiveness of screens and devices.
At Revelry, our design team members can also do front end development, so our designs are involved not only in the design and UX discussions but also the implementation of the UI. Throughout a sprint, designers and developers will tag team tickets: passing a ticket back and forth until both the implementation and design meets our standards and acceptance criteria (AC).