High-Fidelity Prototyping is the creation of detailed, interactive prototypes that closely simulate the final product's look, feel, and behavior. A high-fidelity prototype includes: polished visual design, realistic interactions and animations, actual or realistic content, and functional logic (e.g., a form that validates, buttons that navigate). It bridges the gap between static mockups and production code. Stakeholders can interact with it, test workflows, and provide feedback before engineers build.