Cordero
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Upload a PDF, link, or notes. Explain each idea in your own words. See exactly what you've mastered, and what you haven't.
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 material 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.
Upload a PDF, paste a link, or drop in text.
Cordero splits it into focused study items you can review and curate.
Cordero creates a thorough set of questions, each with an ideal answer.
Answer in your own words and get a score with specific feedback.
Every score is stored and plotted over time, so you see your understanding grow.
Keep mastering more materials.
$0
A small allowance to try Cordero on a short piece of your own material. Loading a sample from our library costs nothing; only the low-cost scoring of your answers uses your allowance, so you can practise the full loop many times before subscribing.
Your subscription is an AI budget of the monthly amount each month. Extracting items and generating questions cost more; scoring an answer costs very little. Unused monthly budget does not carry over. You can add funds any time ($3, $5 or $10) — those stay in your account until you use them. Cancel any time.
Payments are handled by Lemon Squeezy. See our Terms of Use.
Two ways to try Cordero on the Free plan:
Pick up where you left off, or add new material.
Try Cordero on a ready-made sample: load it, answer the questions, and see how scoring works — a quick way to feel the app before adding your own material. Loading is free; only the small scoring cost applies.
New study sets get these values. Study sets that you already have do not change.
Download everything stored for your account — your source materials, all items and questions, your submitted answers, and all scores — as a single JSON file.
Deleting your account permanently removes everything: your study sets, items, questions, answers, scores, and your sign-in. This cannot be undone. Consider exporting your data first.
Turn your own material into practice questions in 3 steps.
Questions need enough information in the item itself. Consider including a definition, explanation, or example.
Both options below process the original source again and use additional allowance. Extraction may bring back items you deleted.
Only if something is missing, like a definition or an example that is not in your material. You can skip this step.
Unsaved draft — kept during navigation in this tab. Refreshing or closing the tab will discard it.
Local-development control, shown only when insecure dev auth is enabled. All UI requests send this value as X-User-Id.