An interactive prototype is a tangible version of a product that a user can interact with and use, from clicking certain buttons to filling out forms (even if certain things in the background are not finalized).
It is usually built in design tools such as Figma, Adobe XD, or Axure, by connecting multiple screens to each other: you click a button on the first screen and it takes you to the second one, you open a menu and it actually opens, you fill in a field and receive an error or confirmation message. It can have different levels of complexity, from simple navigation between screens to simulating different transitions, animations, and states (what a button looks like on hover, what happens when a list is empty).
Because people actually interact with it, rather than just looking at it, an interactive prototype shows things that a simple static image cannot show, for example, whether the flow between screens makes sense, whether users can find buttons and menus on their own without explanations, where they hesitate or get stuck in real time. It is the closest way to test the “feel” of using the product without it having actually been built yet.
It is the main tool for usability testing and validation testing, in which users are given a task (“find product X and add it to the cart”) and interact with the prototype as if it were the real product. It is also used in presentations to clients, where an interactive prototype communicates the idea much more clearly than a set of static images, and to align the development team on the exact expected behavior before writing the code.
An interactive prototype remains a simulation, not the real product. Even though it can look and behave convincingly, it usually does not have the real logic behind it (complex validations, connection to databases, real performance), which is worth clarifying when it is tested with users or presented to clients.
