A study notebook that does the remembering
Study a few minutes a day. Still know it in June.
DeepRetain turns your notes into short questions and brings each one back just before you'd forget it. Answer quickly and correctly and a card waits longer. Hesitate or miss, and it comes back sooner. There's a daily limit, so you can't cram even if you try.
The demo needs no account: two sample decks, three weeks of made-up history, an exam coming up.
Glycolysis
Sprinting muscles run short of oxygen but still make some ATP. Which pathway keeps going, and why?
Glycolysis, in the cytoplasm. It doesn't need oxygen, as long as NAD+ is recycled.
The hare crams. The tortoise reviews.
Two students learn the same idea. One crams the night before a class exam on day 28, then crams again the night before the AP Exam on day 41. The other learns it on day 0 and reviews it four times, each a little later than the last.
By AP Exam morning the crammer remembers about a sixth of it. The tortoise still has most of it, after less total time.
| Recall | Day 28 (exam) | Day 35 (+1 wk) | Day 41 (AP Exam) |
|---|---|---|---|
| Cramming | 100% | 3% | 15% |
| DeepRetain | 94% | 81% | 71% |
Nine ways to study, depending on the day
Every one of them counts toward the same daily limit and moves cards the same way. Auto picks for you: quick taps while a card is new, typing once you know it.
Tired? Tap.
- Multiple choicepick one of four
- True or falseone statement, two buttons
- Flipthink of it, flip the card, say how it went
A word or a sentence
- Fill the gaptype the one missing word
- Writeanswer in your own words
- Say itanswer out loud
Make it stick
- Teach it backexplain it to someone who's never heard of it
Hands-free
- Listenit reads the question, waits, then reads the answer
One account, every device
Start a session on the bus, finish it at your desk. Your settings, the devices you study on and a summary of your progress live in your Auth0 account. Your cards and every answer are stored under that same account in MongoDB Atlas. Your AI key is encrypted before it ever reaches Auth0.
Numbers worth looking at
A calendar of study days, how often you're right and how fast, what's coming up against your limit, how much you'd remember right now, which cards keep slipping, and how many reviews the schedule saved you.
Questions people ask
›Why can't I do more than fifteen a day?
Because the sixteenth review in one sitting is worth much less than the first review tomorrow. Spacing is the whole trick. You can lower the limit any time, or raise it to 25, but a raise only starts the next day.
›What does the AI actually do?
Gemma 4, an open-weight model from Google (Apache 2.0), turns your notes into cards, writes the multiple-choice, fill-the-gap and true-or-false versions, marks written and spoken answers on meaning rather than wording, and explains a missed card another way when you ask. The quick modes are checked against an answer key, and Flip and Listen go by your own rating. Only answers Gemma has marked can move a card into the last box.
›Do I have to pay for anything?
No. Gemma runs on Google AI Studio with your own free key, or on your own machine through Ollama. With neither, a simple offline grader keeps things going.
›Can I use it on my phone and my laptop?
Yes. Your settings, the devices you use and a progress summary are kept in your Auth0 account, and your cards and history are stored under that same account. Sign in on any device and carry on. It can be installed to your home screen too.
›What happens to my notes?
The text is pulled out of the file, you check it, and it becomes cards in your account. The file itself isn't kept. On Google's free tier, prompts may be used to improve their products, so keep private things out of your notes.