Diagnosica serves as an online AI-driven simulation and training platform tailored for medical students in their clinical years as well as for junior doctors. Users engage with a simulated patient through video, utilizing either voice or text for interviews, and they can assess case details, select appropriate lab tests and imaging options, formulate a primary diagnosis along with differential diagnoses, and draft a management strategy. Following the completion of each comprehensive case, the platform generates a competency scorecard that includes feedback on clinical skills and recommends future cases for further practice. Additionally, it offers short cases, lasting two minutes each, providing a quick format for skill enhancement. Designed to facilitate personalized learning across various medical specialties and educational stages, Diagnosica incorporates features to track progress, such as streaks, points, leagues, and leaderboards. While it stands as a valuable educational resource for honing clinical reasoning and communication abilities, it does not function as a medical device, nor does it replace the necessity of supervised clinical training or serve as a simulator for physical examinations. Ultimately, Diagnosica empowers learners to refine their skills in a flexible and engaging manner, enhancing their readiness for real-world clinical environments.