repeat.cards logorepeat.cards

Spaced repetition · FSRS · Both directions

See each word again just before you forget it.

repeat.cards schedules every card with FSRS, the open-source spaced repetition algorithm, and keeps a separate schedule for each direction of the card. You bring the words; it decides when you see them.

Start training — freeWhy two directions ↓
repeat.cards is a spaced repetition flashcard app for language learners. It schedules every card with FSRS, an open-source algorithm that predicts when you are about to forget a word, and tracks the two directions separately: recognising casa and producing it are scheduled on their own. There is nothing to configure.

Add your first words and start

How does spaced repetition decide when I see a word?

Every time you answer a card you rate how it went: Again, Hard, Good or Easy. FSRS turns that rating into a new estimate of how well the word is held, and schedules the next review for the day your chance of recalling it falls to about 90%. A word you remember easily moves out to weeks and then months; a word you miss comes back the same day and climbs again from there.

You do not have to guess what a rating will do. Each of the four buttons shows the interval it will give before you press it, so “Hard” and “Good” are a choice between two dates you can see.

A card mid-review on a phone, above the four rating buttons and their next intervals
Each rating button shows the interval it will give before you press it.

Why each card has two schedules

A vocabulary card can be asked two ways. On the front you see the word and recall what it means. On the back you see the meaning and type the word yourself. The second is harder — you have to produce the spelling, the article, the accent — and it fades faster.

So repeat.cards keeps two complete FSRS states per card, one for each side. Answering one side never moves the other. Here is what that looks like for one word:

You see

Front: recognise
casa
Back: produce
house

You answer

Front: recognise
Recall the meaning, then check
Back: produce
Type the word, then compare

Its own schedule

Front: recognise
Stability, difficulty, next due date
Back: produce
Stability, difficulty, next due date

Typical path

Front: recognise
Moves out quickly once you know it
Back: produce
Comes back more often until you can spell it

Can be mastered

Front: recognise
On its own
Back: produce
On its own

In a new account’s first session the front comes before the back, so nobody is asked to type a word they have not been shown yet.

Fixed intervals, SM-2 and FSRS

Spaced repetition apps differ mostly in how they choose the next date. The table is the short version.

Next review

Fixed boxes (Leitner)
Set by the box a card is in
SM-2
Previous interval times an ease factor
FSRS
Predicted from a model of memory

Adapts to the card

Fixed boxes (Leitner)
Only by moving boxes
SM-2
Through the ease factor
FSRS
Tracks stability and difficulty per card

Aims for

Fixed boxes (Leitner)
Nothing explicit
SM-2
Nothing explicit
FSRS
A recall probability, about 90% here

In repeat.cards

Fixed boxes (Leitner)
No
SM-2
No
FSRS
Yes, for every side of every card

Your pace, not the algorithm’s

FSRS decides when a word is due. You decide how much of it you take on: a limit on new cards per day (20 unless you change it) and on reviews per day (200 unless you change it). If you study past midnight, set the hour your learning day ends, and a late session still counts for the day you think it does. Reached the limit and want more? Add extra new cards or reviews for today without touching your usual limits.

The review forecast shows what those limits add up to over the coming weeks.

Spaced repetition FAQ

What is spaced repetition?
A way of reviewing that waits as long as it safely can before showing you something again. Each successful review pushes the next one further out, so a word you know well comes back after weeks or months, and a word you keep missing comes back soon. You spend your time on the words you are about to lose.
What is FSRS?
The Free Spaced Repetition Scheduler, an open-source algorithm from the open-spaced-repetition project. For every card it keeps an estimate of how stable the memory is and how hard the card is, and schedules the next review for the day your chance of recalling it drops to about 90%. Anki uses it too.
Why are the two directions scheduled separately?
Because recognising a word and producing it are different skills. Seeing casa and knowing it means house is easier than seeing house and typing casa, and the two fade at different speeds. repeat.cards keeps a separate FSRS schedule for each side, so the harder direction gets more reviews without dragging the easy one along.
Do I have to set anything up?
No. Scheduling works from the first card. What you can change is how many new cards and how many reviews you take on per day, and the hour your learning day ends if you study past midnight.
What if I stop reviewing a word I already know?
Mark the card as mastered and it leaves training; you can return it to training at any time. A mastered card is never offered in a session.
Is it free?
Yes. Decks, cards, scheduling, the forecast and the statistics are free, on the web and in a free Android app. Only the AI features run on coins, and every account starts with some.

Bring the words. We'll handle the timing.

Create a deck, add a few words, and the first review is scheduled from your first answer. Free, no credit card.

Get started — free

FSRS for every card · Two directions · Your daily limits

Keep reading

Review forecast

See how many reviews are coming day by day, per deck, at your own daily limits.

Typed answers

Type the word instead of picking it; a letter-by-letter diff shows exactly what was off.

AI flashcards

Type a word and AI fills in the rest of the card: example, audio, mnemonic, picture, grammar.

Pricing

What coins are, what packs cost, and what stays free.