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YAML Formatter

Format, validate & convert YAML

Input YAML
Formatted

About YAML Formatter

A single wrong indent in a Kubernetes manifest or GitHub Actions workflow breaks everything, often with an unhelpful error message. Paste your YAML here and find out if it is actually valid before you apply it. The validator catches indentation errors, duplicate keys, and syntax issues, and shows exactly where the problem is. The formatter normalises indentation consistently across the whole document. One-click conversion between YAML and JSON is there when you need it — common when an API speaks JSON but your config system expects YAML.

Common Use Cases

  • →Validating Kubernetes manifests and Helm charts before kubectl apply
  • →Debugging GitHub Actions and GitLab CI pipeline files
  • →Normalising indentation in Docker Compose files
  • →Converting JSON API output to YAML config format

Frequently Asked Questions

Why is YAML indentation so unforgiving?+
Unlike JSON which uses braces, YAML uses indentation to define structure. A misindented line changes the nesting level and completely alters the meaning of the document — often without an obvious error.
Can I use tabs?+
No. The YAML specification bans tab characters for indentation. Spaces only. The validator flags tabs as an error.
YAML vs JSON — when to use which?+
YAML is more readable for configuration (especially multi-line strings and comments) but more error-prone to write. JSON is stricter, more widely supported in APIs, and easier to validate programmatically.
What does the JSON to YAML conversion do with types?+
JSON types map directly: strings stay strings, numbers stay numbers, booleans stay booleans, null stays null, arrays become YAML sequences, objects become YAML mappings.