UI Design represents the graphical side of the project. This design is based on the sketches that are made at the beginning stage of website/application development and on the technical requirements. The UI development stage includes deciding on whether to include animation or video-backgrounds, and on choosing a unique layout in order to stand out. Thus, UI covers all graphical elements that move the development project to the next level.
UX Design is the more analytical and technical part of website/application development. It involves the process of improving the convenience, and hence the pleasure, of navigating through the website/app. A well-designed UX, will make the interaction of your customers with your product a satisfying experience, which, in turn, fosters customer loyalty.
Interaction design helps assuring high-level usability of your website/application. It covers all dynamic elements, such as links, buttons, and forms, and takes care of all the actions that have to follow them. The main output of interaction design is the sitemap.
Why are these steps needed?
These 3 steps assure a user-friendly process of registering, ordering, contacting, and finding new information. An unclear or ill-functioning website/application will annoy your users and this negative experience will then be associated to your brand. By taking the time to do these steps properly, your users will be able to navigate intuitively, which will increase the time that they'll spend with your product. Ultimately, this will lead to an increase in your conversions, sales, or brand awareness.