Free Online YAML Formatter & Validator
Format and validate YAML instantly. Detect syntax errors, convert YAML to JSON or JSON to YAML, and beautify configuration files for Kubernetes, Docker Compose, GitHub Actions, and more.
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Frequently Asked Questions
What is YAML and why is it used?
YAML (YAML Ain't Markup Language) is a human-readable data serialization format used for configuration files. Its indentation-based syntax makes it popular for Docker Compose, Kubernetes, CI/CD configs, and application settings.
What are common YAML syntax errors?
The most common errors are incorrect indentation (tabs are not allowed — use spaces), missing colons after keys, and unescaped special characters in string values. This formatter validates and fixes indentation.
What is the difference between YAML and JSON?
YAML is a superset of JSON — all valid JSON is valid YAML. YAML adds comments, multi-line strings, and a cleaner syntax without quotes and braces. JSON is more compact and universally supported in APIs.