Know how well you actually understand it.

The most effective way to master a topic is to explain it in your own words. Cordero turns that principle into a simple, repeatable workflow.

Cordero unites three proven ideas into a single loop. Active recall: you explain each concept in your own words instead of just rereading. Feedback: Cordero scores your answer against an ideal one and shows exactly what you missed. Adaptive practice: it keeps bringing back the ideas you haven't mastered yet, so your time goes where it counts — and you watch your progress climb across four levels as weak spots turn into strengths.

It starts with your own material. Feed Cordero a PDF, a URL, or plain text; it breaks the content into focused study items and generates a thorough set of questions and ideal answers to test you. You curate items, add your own, and delete any you don't want.

Your subscription pays for the AI, directly and transparently. The AI models that generate your questions and score your answers cost real money, so your monthly subscription works like a budget — each AI task uses a little of it. It refreshes every month, and you can top up if you need more.

Free use for initial exploration. Every account starts with a small free allowance to try Cordero on a short piece of your own material. A ready-made library with questions already prepared lets you practice further — there, only the low-cost scoring applies, so you can run the full loop many times before subscribing.