BROWSER-LOCAL YAML TOOL

Format and validate YAML safely.

Check YAML syntax, duplicate keys, documents, anchors and aliases. Custom tags are preserved and never presented as lossless JSON.

No upload25 MB limitAlias limits

Choose a YAML fileor drop it here · maximum 25 MB

or paste YAML

See YAML-specific structure

The summary reports documents, anchors, aliases and custom tags instead of treating YAML as relaxed JSON.

Format and validate

Duplicate keys and invalid syntax produce clear errors. Alias expansion is limited to protect the browser from unusually complex input.

Your YAML stays local

File and pasted contents are processed locally. Ordinary page and asset requests still reach the hosting provider.