Nikki AI
日記 · Your daily Japanese
Learn Japanese the way
you'll actually use it.
Read it, hear it, write it, say it — one app that does all four. Start with hiragana and katakana, then grow through guided story-lessons with a talking cast of characters, speaking practice that marks your pronunciation word by word, a grammar library you can review, smart flashcards, and a Japanese journal that gives you instant feedback. And whenever you get stuck, ask anything and keep the answer as a flashcard.
Research shows a strong link between writing and speaking fluency — so daily writing practice sits at the heart of everything you do here.
Based on research from the University of Wisconsin–Madison and other leading institutions
Start Learning Free
Free to start · iOS, Android & web
Read · Listen · Write · SpeakJLPT N5–N1iOS · Android · WebAI-powered feedbackAsk anything
こんにちは、日記です。
読む · 聞く · 書く · 話す
A complete system, not another single-skill app
Most apps train one skill and leave you to find the rest elsewhere. Nikki teaches you to read, listen to, write and speak Japanese in the same place, on the same material, from the same daily habit.
読む
yomu
Reading
Real Japanese from your first lesson — never a wall of text you have to decode alone.
- Hiragana and katakana for complete beginners
- Story-lessons written in Japanese, N5 through N1
- Tap any word for its reading and meaning in context
- A grammar library that explains every pattern you meet
聞く
kiku
Listening
Every line is spoken aloud by a recurring cast, so the language reaches your ears as well as your eyes.
- Natural voices for every character in every scene
- Play a whole scene through, or replay a single line
- Follow along with the text as it is spoken
書く
kaku
Writing
Produce the language yourself, every day, and find out immediately what worked and what did not.
- A Japanese journal with line-by-line feedback
- Graded writing questions inside lessons
- Kanji and kana writing practice — mobile app only (iPhone and Android)
- Type kana with no setup — romaji converts as you go
話す
hanasu
Speaking
Talk with Nikki, say the lines back, and find out what actually landed — not whether you feel confident, but which sounds you missed.
- Live Journal: answer Nikki’s questions aloud and hear her corrections
- Say any lesson line aloud and see it marked word by word
- Or shadow it: the line keeps playing, the words stay hidden
- Every mistake highlighted, with the beat you missed named
- Lesson practice is recognised on your own device, never uploaded
And it all connects. A word you hear in a lesson is a line you can say back, a flashcard, grammar that goes into your review queue, and you use it in tonight's journal entry — with feedback the moment you finish writing.
See it in action
A calmer, warmer place to learn
Explore Nikki on the web, iPhone and Android. Kanji and kana writing practice is available in the mobile app only.
Write
Journaling with instant feedback
Write about your day in Japanese and get line-by-line corrections, a plain-English read-back, and a cleaner version to learn from.
New: Live Journal
Talk about your day with Nikki, in Japanese
Nikki asks you a question aloud. You answer aloud. She explains your mistakes. Then she says the correct sentence.
Live Journal is on the website and in the phone app.
Finish
Record
It remembers what you know
Watch what you know grow
Nikki tracks how well you know each kanji, word and grammar pattern. It uses that record to decide which readings to show and what to review next.
Familiarity seals
A seal on everything you learn
Every kanji, word and grammar pattern you meet gets a seal. The bonsai on the seal grows as you read, practise and review. Each row shows the seal for kanji, words and grammar.
Kanji
Words
Grammar
- NewYou met it in a lesson or a story.
- LearningYou read it without help, or you answered it correctly in practice.
- FamiliarYou kept it for a few months.
- MasteredYou kept it for about a year.
- Read a word in a lesson without tapping it for help, and its seal climbs.
- The app plans each review around how well you remember the item.
- Mark something you already know, and it leaves your reviews.
Adaptive furigana
Readings that go away as you learn
Furigana are the small kana above a kanji that show how to read it. Nikki shows them while you learn a word. When the word reaches Familiar, its reading goes away, and you read the kanji yourself.
友達と駅で会って、一緒に映画を見ました。
Every word you are still learning shows its reading.
友達
Learning
駅
Learning
会う
Learning
一緒
New
映画
New
見る
Learning
Tap a word in the app to see its reading again. To keep every reading, turn off “Hide readings as you learn” in Settings.
One app, the whole journey
Everything you need to actually get fluent
Five tabs, an Ask button that follows you everywhere, one daily habit — here is what you actually open the app to do.
Learn
Start with hiragana and katakana
Completely new to Japanese? Start with hiragana and katakana, learn their sounds, and build confidence reading your first characters before moving on to words and stories.
Learn
Guided story-lessons
Short, voiced scenarios across JLPT N5–N1. Meet the scene, learn the grammar behind it, then practice — with a recurring cast of characters who speak each line.
Learn
Listen, tap & understand
Play a whole scene end to end, or line by line. Tap any word to see its reading and meaning in context — furigana included, nothing left a mystery.
Learn
Say it back, and see what landed
Hear a line, say it back, and watch your words appear as you speak. Every sound that missed is highlighted — tap one for its meaning and hear it again. Recognition happens on your own device; your voice is never uploaded.
Learn
Shadowing, with the words hidden
The harder exercise, and the one that builds speed. The line keeps playing while you speak a beat behind it, and the words stay hidden — so you are listening and producing at the same time, the way real speech asks you to.
Learn
A grammar library that comes back to you
Every pattern you meet is saved to a browsable library with clear examples. Essential patterns are flagged, and you never have to build a study list — the ones you're about to forget come back for review on their own.
Write
Journaling with instant feedback
Write about your day in Japanese and get line-by-line corrections and tips. Then read your own entry aloud and see which of your words landed. Type kana with no setup — romaji converts as you go.
Learn
Kanji and kana, by hand
Practice writing kanji, hiragana and katakana by hand in the mobile app only, on iPhone and Android. Follow the strokes, then practice from memory. Kana lessons and reading practice are also available on the web.
Learn
Seals that mark what you know
Every grammar point, kanji and word carries a seal: New, Learning, Familiar or Mastered. Mark something you already know, and it leaves your reviews. Read a word enough times without help, and its seal climbs on its own.
Learn
Study ahead, a card at a time
A short daily set that teaches new kanji, words and grammar before a lesson asks for them — one card at a time, at the level you chose, so nothing arrives cold.
Review
Smart flashcards, made by AI
Turn any sentence into a flashcard. “Super Flashcards” fill in the missing side and add a grammar breakdown automatically, then spaced repetition schedules your reviews.
Every screen
Ask anything, keep the answer
Any Japanese question, from anywhere in the app — grammar, a word, or how to say something right now. You get one sentence you can really use plus a breakdown of every part, then turn it into flashcards in a single tap.
Home
Progress that grows with you
Earn XP and level up as you write, review, and finish lessons — and watch a bonsai grow from your daily practice. Gentle reminders keep the habit alive.
And everywhere you use it
- iPhone, Android and the web
- Home-screen widgets
- Dark mode
- Adjustable text size
- Furigana that fades as you learn
質問 · Ask
Stuck on something? Just ask.
Ask any Japanese question, from anywhere in the app, and get a clear answer in seconds — then turn that answer into flashcards in one tap. The thing you were confused about a minute ago is now in your review queue.
Ask in your own words
A grammar point, a word you half-remember, the difference between two things that look identical — or something you simply need to say today. Type it in English or in Japanese.Get an answer you can actually read
One Japanese sentence you can really say, then a breakdown of every piece of it. Kana sits above the kanji, and you can tap any word for its meaning or hear it read aloud. Never romaji.Keep it — one tap
Turn what you just learned into flashcards, pitched at your JLPT level, and save them to a deck. They join your review queue and come back before you forget them.
Ask
How do I say “I’m running late” politely?
少し遅れそうです。
It looks like I’ll be a little late.
- 少しa little
- 遅れるto be late, to run behind
- 〜そうですit looks like it is going to happen
Say it in Japanese
I'm running a little late.
少し遅れそうです。
On every screenAnswers pitched at your levelOne tap to a flashcard
The Ask button follows you through the whole app — mid-lesson, mid-review, halfway through tonight's journal entry. That is where the questions actually come up.
Web app · sample progress shown
The Shore
Send a message in a bottle
Write a few lines in Japanese and seal them in a bottle. The sea carries it to another learner, who can read it and write back.
- Write your note in Japanese. You can also start in English and turn it into Japanese.
- Before the bottle sails, Nikki reads your Japanese and suggests corrections.
- Another learner finds it. They can write a reply, or let it drift to someone else.
- A journey bottle visits five learners and comes home with a note from each one.
Every note passes a safety check before it sails. Senders stay anonymous, and you can report a note or block its sender.
The Shore opens with a subscription at learner level 5.
Collect glass as you study
Lessons, journal entries and reviews can leave a new bottle on your shore. Put your favourite bottles on your shelf.
The Pond
Catch fish with the words you know
Cast a line and hook a fish. Each right answer brings the fish closer, and each wrong answer lets it swim back.
- The questions use only words you have already studied, so fishing is review, not new work.
- The questions get harder as the fish comes closer, with more words that look alike.
- An elite fish ends with a kanji puzzle: build the word from two tiles.
- Some fish appear only in certain seasons, or only at night.
- Keep a fish in your pond, or release it. The almanac records every species and your longest catch.
The Pond opens with a subscription once you know 24 words.
Web app · sample progress shown
Fish from the rivers and seas of Japan
Every fish carries its Japanese name, so each catch is one more word to read.
鮎
Ayu · sweetfish
山女魚
Yamame · cherry trout
鯉
Koi · carp
鯛
Tai · sea bream
鯰
Namazu · catfish
鰻
Unagi · freshwater eel
はじめましょう · Let's begin
Start your Japanese journal today
A few minutes a day of reading, listening, writing and speaking — one system, guided the whole way. Free to start on iOS, Android and the web.
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