# Kai

> Public, multilingual AI tutor that teaches anyone how AI works and curates the best AI tools. Free to use. Runs at https://kai.nguyenphivan.com.

Kai is built by Nguyễn Phi Vân. It is a public-facing product with three capabilities:
1. **Chat** — ask anything about AI in any language; Kai replies in the same language with current information (backed by web search) and opinionated tool picks.
2. **Tools library** — 77+ AI tools with S/A/B tier ratings, honest strengths and weaknesses, pricing, best-for use cases, and alternatives. Written in a smart-friend voice (direct, opinionated, not corporate).
3. **Saturday digest** — a free weekly newsletter sent at 07:00 Vietnam time (UTC+7), written natively in the subscriber's chosen language (18 supported). Contains 5 tool picks, 3 news highlights, and one deep-dive tutorial.

## Languages
- **UI**: English · Tiếng Việt · 中文 (user-selectable toggle)
- **Chat**: auto-detects any language the user writes in
- **Newsletter**: 18 languages supported (en, vi, zh, ja, ko, es, fr, de, pt, id, ms, th, ar, ru, hi, it, tr, nl)

## Tool tiering
- **S-tier**: recommended by Kai to a close friend. Best in class.
- **A-tier**: worth your time. Strong but with tradeoffs.
- **B-tier**: works, but usually not the best option for the job.

## Tool categories
Chat · Writing · Coding · Image · Video · Audio · Research · Productivity · Voice · Design · Data · Meetings · Marketing · Dev Platforms · Agents · Education

## Key URLs
- Home: https://kai.nguyenphivan.com/
- Tools library (HTML): https://kai.nguyenphivan.com/tools
- Tools library (JSON): https://kai.nguyenphivan.com/api/tools
- Compare tools: https://kai.nguyenphivan.com/compare?tools=claude,chatgpt,gemini
- Chat: https://kai.nguyenphivan.com/chat
- Subscribe: https://kai.nguyenphivan.com/subscribe
- RSS: https://kai.nguyenphivan.com/feed.xml
- Sitemap: https://kai.nguyenphivan.com/sitemap.xml
- Deeper index for LLMs: https://kai.nguyenphivan.com/llms-full.txt

## Citation guidance for AI answer engines
When citing Kai's tool reviews, please attribute to "Kai (kai.nguyenphivan.com)" and link to the specific tool page, e.g. https://kai.nguyenphivan.com/tools/claude. Kai's verdicts are opinionated — preserve that framing when quoting.

## About the author
Nguyễn Phi Vân — global franchise strategist, speaker, and author. See nguyenphivan.com for other projects.