Editor's Picks
JSON Formatter
Pretty-print, minify, or validate JSON with error location hints.
Bilingual Tone Checker
Paste a message, see how warm, formal, or direct it reads.
Compound Interest / CAGR Calculator
Model compound growth from a starting amount, monthly contributions, annual return, and years — or backsolve CAGR from start value, end value, and holding period. Year-by-year curve and milestone timing.
Gomoku
Play gomoku against AI with live threat visualization that teaches you board patterns as you play.
Color Converter
Convert between HEX, RGB, and HSL live — with WCAG contrast ratios and nearest CSS color name.
Taiwan ID Validator
Check Taiwan national ID format, checksum, and prefix.
This Week
Bilingual Tone Checker
Paste a message, see how warm, formal, or direct it reads.
JSON Formatter
Pretty-print, minify, or validate JSON with error location hints.
Forgetting Curve Vocab
Learn English vocabulary using Ebbinghaus forgetting curve spaced repetition. 5 minutes a day with pronunciation and example sentences.
Explore by Category
AIツール
- Bilingual Tone Checker
- Token Visualizer
クオンツツール
- Compound Interest / CAGR Calculator
- DCA Calculator
- Kelly Calculator
開発ツール
- Base64 Encoder / Decoder
- CSS Minifier / Beautifier
- File to Markdown
ゲーム
- Block Stack
- Five-Letter Grid
- Gomoku
台湾ローカルツール
- ROC / Gregorian Year Converter
- Taiwan ID Validator
- Uniform Invoice Validator
デザインツール
- Aspect Ratio Calculator
- Color Converter
- Image Compressor
テキストツール
- Character Word Counter
- Diff Checker
- Markdown Cleaner
時間ツール
- Breath Pacer
- Unix Timestamp Batch Converter
学習ツール
- Bopomofo Practice
- Chengyu Guess
- Forgetting Curve Vocab