⚡AI Translation & Proofreading

Speed meets accuracy.

AI-powered translation, proofreading, and learning — in one place.

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Free sign-up — no credit card. Unlock proofreading, word explanations & more.

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Three-column translation at a glance

View input, proofreading, and translation side by side.
Highlighted corrections and word explanations help you master accurate expression.

✍️ Input

昨日お店に行ったで、パーティーのためにいっぱい物を買った。私と友達はすごく興奮的だった！

🎩 Formal😎 Casual📧 Business📱 Social

🌐 Translation

😎 Casual

Yesterday I went to the store and bought a bunch of stuff for the party. My friend and I were really excited about it!

Natural, casual English translation. Converts Japanese colloquial expressions into everyday English.

💡 Learning hints

いっぱいa lot, plenty (casual)

ワクワクexcited, thrilled

🔍 Proofread

昨日お店に行ったで行って、パーティーのためにいっぱい物を買った。私と友達友達と私はすごく興奮的ワクワクだった！

1行ったで → 行って — use te-form to connect clauses

2私と友達 → 友達と私 — put others first in Japanese

3興奮的 → ワクワク — more natural Japanese expression

Features

More than just translation

Translation, proofreading, and learning tools in one place.
Everything you need to communicate accurately.

🌐

Fast AI translation

Auto-detects the input language and translates seamlessly between your native and target languages. Results stream in real time via SSE.

Japanese→English

来週の打ち合わせに参加できますか？

Can you attend the meeting next week?

✍️

Proofreading

Automatically proofreads text written in a non-native language. Corrections are highlighted inline with explanations for each fix.

I wants want to goes go to the store and buyed bought some items.

🎨

Customizable tone tags

Translate and proofread in the right register — formal, casual, business email, and more. Fine-tune with follow-up prompts.

🎩 Formal😎 Casual📧 Business email📱 Social media👋 Friendly🎓 Academic

📚

Word explanations & examples

See meanings, nuances, and usage tips for key words and phrases in your translation, complete with example sentences. Learn as you translate.

attendTo be present at (used in formal contexts)

"I will attend the conference tomorrow."

in advanceBefore the expected time; ahead of time

"Please let me know in advance."

Desktop App

Translate from any app
in an instant

One shortcut key to instantly translate selected text. Works in your browser, email client, chat app — anywhere.

✓Global shortcut (Cmd + J / Ctrl + J) for instant launch
✓Selected text is automatically loaded into the input
✓macOS / Windows supported

Download formacOS ⊞Download forWindows

⌘+J

Select text in any app,
⌘ + J press
Translation appears instantly.

Languages

5 major languages supported

Covers the key business languages.
Auto-detection means you just type and get the right translation.

🇯🇵Japanese日本語

🇺🇸EnglishEnglish

🇨🇳Chinese中文

🇰🇷Korean한국어

🇪🇸SpanishEspañol

More languages coming soon

Security & Privacy

Security you can trust

Designed with privacy first to protect the confidential information you handle at work.

Never used for AI training

Your input text and translations are never used as training data for AI models. Translate confidential documents with confidence.

History stays on your device

Translation history is stored only on your device and is never sent to a server. You always stay in control of your data.

Pricing

Simple pricing

Start free and upgrade only when your workflow grows.

Free

$0 / month

Enough for everyday translation

✓Up to 4,000 chars per request
✓200,000 tokens per month
✓AI translation + proofreading
✓Phrase explanations & examples
✓Tone tags & follow-up
✓Desktop & Web apps

Start free

Pro

$9.99 / month

High-capacity plan for professionals

✓Up to 100,000 chars per request
✓2,000,000 tokens per month
✓All Free plan features
✓Long-form document translation
✓Priority support

Upgrade to Pro

FAQ

Frequently asked questions

Nico is an AI-powered translation and proofreading app. Beyond translation, it proofreads your foreign-language text, explains key vocabulary with example sentences, and provides everything you need for accurate cross-language communication — all in one place.

Currently Japanese, English, Chinese, Korean, and Spanish. French, German, Portuguese, and more are planned for future releases.

Translation, proofreading, and learning features are the same on both. The Desktop app adds a global shortcut (Cmd+J / Ctrl+J) for instant launch and direct translation from text selections — conveniences unique to desktop.

Yes. On the web you can try up to 5 translations (400 characters each) without signing in. After registration, the Free plan gives you 200,000 tokens per month.

Translation history is stored only on your device and never synced to the cloud. All communication is encrypted via HTTPS. Your input text is never used to train AI models.

When you enter text in a non-native language, Nico highlights grammar and usage corrections inline alongside the translation. Each correction includes an explanation, and tone-tag selections trigger tailored rewrite suggestions.

Yes, you can change or cancel your plan at any time from the settings page.

Use foreign languages with more confidence

Translate, proofread, and learn in one place with Nico. Start free in seconds.