YAML formatter/validator · Guide
Common YAML Mistakes
YAML’s flexibility hides a few sharp edges. These are the mistakes that cause most failures.
Tabs and inconsistent indent
Tabs are not allowed, and mixing indentation widths within a block changes meaning. Keep indentation uniform and spaces-only.
Unquoted special values
Bare yes, no, on, off and version-like numbers are interpreted as booleans or numbers. Quote them when you mean the literal string.
Frequently asked questions
Can I use this for production work?
Yes, for inspection, formatting and quick generation. Still review the output before committing it to production code or configuration.
Ready to try it?
Open the free browser-based YAML formatter/validator and apply what you just read — no sign-up, runs locally.
Open the YAML formatter/validator tool