Bring it back
- Reviews of what you finished earlier
- At most a third of your time
- Answers first, then the check
Warm up
A gym for thinking and learningThree sets a day.
Three sets a day.
What you learn stays.
Renfy turns anything you want to learn into a short daily workout, with a patient tutor beside you and a memory that won't let it fade.
No sign-up to try. Start with a 7-day free trial.
Try one set
Feel it in a minute.
Learn one idea, answer one question, then recall it. That is a set. No sign-up, nothing to install.
Sample set, step 1 of 3: learn
Why spacing beats cramming
Right after you learn something, you forget it quickly. Then the forgetting slows down. Each time you bring it back just as it starts to slip, it fades more slowly than before. That is why the same hour of study, spread over several days, sticks longer than the same hour in one sitting.
You learn a new idea on Monday. When is the best time to go over it again?
Pick one to see what the tutor says.
Tutor, on the answer Straight away:Not quite, and it is a very natural guess. Going over it straight away feels good because it is still easy, and easy practice does little for memory. The better moment is a day or so later, when it takes a little effort to pull back.
Tutor, on the answer A day or so later:Yes. A day later it has started to slip, so bringing it back takes some effort, and that effort is what makes it last. The next gap can then be longer: a few days, then a week.
Tutor, on the answer The night before:That gets many people through one exam, and most of us have done it. But it fades again within days. The same time spread out keeps it far longer, so a day or so after learning is a better moment.
Sample set, step 2 of 3: recall
What did you just take away?
Say it to yourself in your own words first. Then check.
Show a takeaway
One way to put itGo over it just as it starts to slip, then wait a little longer each time.
How did yours compare?
Sample set, step 3 of 3: done
Set complete
- Learned one idea
- Answered one question
- Recalled it in your own words
You had it, so the next gap can be longer.
Not yet is fine. That is exactly what the coming back is for.
In the real thing, this comes back tomorrow, then in 3 days, then 7.
This is a sample, so nothing here is saved. The real tutor adapts to you: your goal, your pace and your answers.
How a day works
Three sets. Then you're done.
No endless feed and no guilt. Renfy plans today's session for the time you have, and tells you when to stop.
Learn one thing well
- One new section, in order
- A tutor that explains and asks
- It waits for you to think
Learn
Try it yourself
- Three problems on the last section
- Hints when you are stuck
- Never the spoiler
Practise
Screenshots on this page use sample data.
What makes it stick
You forget on a curve. Renfy trains against it.
Everything you finish comes back for a short review after 1, 3, 7, 14, 30 and 60 days: right when it is about to fade.
Spaced reviews
Every set ends with a way back.
Finish a lesson and Renfy books it to return after 1, 3, 7, 14, 30 and 60 days, each time as a short check just before it would fade.
- A calm finish, never a lecture
- The next set is one tap away
- Reviews fill the start of each day
Takeaways and recall
Say it in your own words.
End a section with a one-line takeaway. Every one lands in your notebook, and comes back in your reviews and in short recall drills, so you remember your own words instead of rereading.
- Searchable, and filtered by track
- Recall first, then check
- Yours to download any time
Your week in review
See what held up, and what is fading.
A weekly goal you set, a calendar of the last 26 weeks, and each track's pace and finish estimate. Time is an honest estimate, never padded.
- Nothing to collect and nothing to chase
- Outside study counts too: log it
- Private unless you share
Tracks for any subject
Pick a track, or have one built.
Start from one of eleven ready-made tracks, paste a reading list you already have, or tell the tutor your goal and it designs a plan from the best free material on the web.
Python
JavaScript
SQL
Git
Classic algorithm problems
Linear algebra
Calculus
Statistics
Machine learning
Dive into Deep Learning
Economics
Or have one built
“Understand transformers well enough to build one”
Ready-made tracks, or have one built for your goal
- Python
- SQL
- Linear algebra
- Calculus
- Statistics
- Machine learning
- Git
- Algorithms
- Economics
- JavaScript
- Deep learning
Example profile
M
MayaTraining here since March 2026
@mayaLinear algebra
Solid
Python
Solid
Probability
Building
SQL joins
Fading
When Maya says she's very sure, she is right about 9 times in 10.
Takeaway, PythonA dict is a shelf of labelled boxes.
Takeaway, mathsA matrix is a machine that moves space.
Takeaway, SQLA join lines up rows that share a key.
A profile that can't be faked
Show what you actually know.
Here is what an example profile looks like. Not trophies or streak counts. Your public page shows what you know today, how well it has held up, and how honest your confidence is.
- Strength comes from reviews you really passed.
- What you stop practising visibly fades.
- Private until you switch it on, and you choose what shows.
Simple prices
Try it free first.
Start with a 7-day trial, about four half-hour sessions. Then pick the pace that suits you.
- Free trialFree for 7 daysabout 4 half-hour sessions over 7 days
- Steady$19 a monthabout 15 half-hour sessions a month
- Daily$39 a monthabout 30 half-hour sessions a month
- Own key$7 a monthno limit: you pay your AI provider directly
