Brilliant

Brilliant is an interactive learning platform for math, computer science, and science, built by curriculum developers from MIT, Harvard, Stanford, Cornell, and Caltech, serving 10 million+ learners with 100,000+ five-star app store reviews. Lessons use visual, step-by-step guidance designed to build real understanding rather than memorized answers, adaptive difficulty adjusts to the learner, progress tracking identifies specific knowledge gaps, and gamification (streaks, levels, daily goals) supports consistent practice. Content spans grade 5 through college-level material, available on both mobile and web. Subscribe and pricing links exist but exact rates aren't shown on the homepage; a free trial is typically offered. Good fit for a self-directed learner who wants to build genuine conceptual understanding in math or CS through interactive, visual problem-solving rather than passive video lectures.