YAML ↔ JSON ↔ TOML Converter
Live 3-way converter between YAML, JSON, and TOML. Smart schema detection for Kubernetes, Docker Compose, GitHub Actions, plus YAML pitfall warnings (Norway problem, octal, sexagesimal). 100% browser-based.
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Frequently Asked Questions
What is YAML?
YAML is a human-readable data serialization format. It is widely used for configuration files in Kubernetes, Docker Compose, GitHub Actions, and similar tools. Structure is expressed through indentation rather than curly braces.
What is the biggest difference between YAML and JSON?
YAML represents hierarchical structure using only indentation — no quotes or curly braces — making it easier for humans to read. JSON requires all keys to be quoted and is more optimized for machine processing.
Is TOML conversion also supported?
Yes, 3-way conversion between YAML, JSON, and TOML is fully supported. TOML files such as Cargo.toml in Rust projects or Hugo configuration files can also be processed.
What happens if YAML indentation is wrong?
YAML is very sensitive to indentation. Use spaces instead of tabs, and all items at the same level must have the same number of indentation spaces. The tool detects indentation errors in real time and warns you.
Are YAML pitfalls like the Norway problem or octal numbers also detected?
Yes, the tool detects the Norway problem — where values like 'no', 'yes', 'on', 'off' are parsed as booleans in YAML 1.1 — as well as cases where numbers are incorrectly interpreted as octal, and displays appropriate warnings.
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.
Help us improve this tool
Share what you like, what needs work, or features you'd like to see