YAML ↔ JSON ↔ TOML 変換ツール

YAML · JSON · TOML Converter

YAML, JSON, and TOML are the three most common config formats. This tool keeps all three in live sync: type in any editor and the other two update instantly. No convert button, no refresh.

Features

• Live 3-way sync across YAML, JSON, and TOML
• Auto schema detection — recognizes Kubernetes, Docker Compose, and GitHub Actions
• YAML pitfall warnings — flags 4 common gotchas before they bite
• Template library — K8s Pod, Deployment, Docker Compose, GitHub Actions, generic config
• Per-format copy & download
• Mobile tab view for narrow screens
• Client-side only — input never leaves your browser

5 YAML gotchas this tool catches

1. yes / no become boolean

Unquoted yes, no, on, off (any case) are parsed as true/false. The "Norway bug":

country: NO       # → false
country: "NO"     # → "NO"

2. Leading zero = octal

01234 becomes 668 in decimal. Quote zip codes, IDs, product codes.

3. Colons trigger base-60 parsing

1:30 becomes 90. Quote time values and Git SHAs.

4. No tabs for indentation

YAML forbids tab indentation. Use 2 or 4 spaces consistently.

5. Quote version & date strings

Values like 1.0 or 2026-04-18 are coerced to number/date. Always quote API keys and version strings.

Related tools

• JSON Parser / Formatter — dedicated JSON editor
• Character Counter — check file size
• Text Diff — compare two files