Please rotate your device to portrait mode
Welcome to
Fast, focused, built for daily progress
Japanese now · more languages on the way
Look anything up in the Dictionary tab.
Add any word straight to your flashcard decks.
In a hurry? Import a word list from any deck’s drawer.
Cards can show the reading, or not.
Every deck sets its own. Change it any time in deck settings.
You don’t pick what to review. Jengo does.
Today you quiz a word until you get it right.
Then it goes quiet for a few days.
It comes back right before you would forget it.
So a session ends sooner than you expect. Nothing is hidden. Those cards are not due yet.
Say you learn 10 a day.
It only works if you come back every day.
What an account unlocks
An account unlocks our best features, cross-device sync, and saved progress.
Share of each week's signups still reviewing cards in later weeks.
Ranked by how many people used it, not how many times it ran.
Language
Show statistics for
Jengo brings Japanese dictionary lookup and spaced-repetition flashcards into one app, with offline study and sync between iPhone and the web.
Version 2.2.1 · Web 4488ef4
Dictionary, kanji, and radical data come from the Electronic Dictionary Research and Development Group (JMdict, KANJIDIC2, and KRADFILE/RADKFILE) under the CC BY-SA licence.
Example sentences are from the Tatoeba Project (CC BY 2.0 FR). Kanji stroke-order data is from KanjiVG (CC BY-SA 3.0).
.txt — one word per line
食べる 飲む 走る
.csv — lemma column required; surface and pos optional. Without a header, first column is used as lemma.
lemma,surface,pos 食べる,食べ,動詞
.json — array of strings or objects with a lemma key
["食べる", "飲む"]
// or
[{"lemma": "食べる", "surface": "食べ", "pos": "動詞"}]
All files must be UTF-8 encoded. Only lemma is required.
Manage your word database from a deck’s drawer (Browse cards).
The probability you'll remember a word when it comes up for review. 0.90 is the recommended default — it's the value the scheduling algorithm is calibrated around, and it balances review workload with solid retention. Lower values (e.g. 0.80) space out reviews more but you'll forget more often; higher values (e.g. 0.95) keep retention very high but can significantly increase daily reviews.
Runs coordinate-descent optimization on your review history to improve scheduling accuracy.
| ID | Lemma | Timestamp | Rating |
|---|
Reminders keep firing for a week even if you don't open the app.
Young = reviewed, interval under 21 days · Mature = 21+ day interval
The share of due reviews you actually recalled, measured from your history. Mature cards (21+ day interval) are the truest signal — aim for them to sit near your target.
No flashcard decks yet. Create a deck to see its stats here.
Learning = in (re)learning steps · Young = under 21-day interval · Mature = 21+ day interval
How often you remember cards when they come up for review.