YAML Formatter

Online YAML Formatter

YAML is the config-file format behind Docker Compose, Kubernetes manifests, GitHub Actions, and countless application settings files — and it's whitespace-sensitive, so a single misaligned line breaks the whole file. This formatter normalizes indentation, validates the syntax, and flags exactly where a file breaks.

Features:

  • Format: Re-indent YAML consistently at 2 or 4 spaces.
  • Validate: Parse the document and report the exact line where syntax breaks.
  • Convert to JSON: Turn valid YAML into equivalent JSON instantly.
  • Client-side only: Your config files and secrets never leave your browser.

1. Why YAML Breaks So Easily

YAML uses indentation, not brackets, to represent structure — which makes it readable but fragile. The two most common failure modes: mixing tabs and spaces (YAML requires spaces only), and indenting a sibling list item or key by a different amount than the one above it.

2. YAML vs JSON

YAML is a superset of JSON in terms of what it can represent, but trades JSON's explicit brackets and quotes for indentation and unquoted strings — more readable for humans hand-writing config files, less forgiving for a parser. Need to move between the two? Use the JSON ↔ YAML Converter.

3. Common YAML Uses

• CI/CD pipelines: GitHub Actions, GitLab CI, CircleCI
• Container orchestration: Kubernetes manifests, Docker Compose
• Application config: Spring Boot, Ansible playbooks
• API specs: OpenAPI/Swagger definitions

Does formatting change my YAML data? No. Formatting only normalizes indentation and spacing. Keys, values, lists, and nested structures stay the same.
Why does my YAML fail to parse? The most common causes are mixing tabs and spaces (YAML requires spaces only), inconsistent indentation between sibling items, or a missing colon-space after a key.
Can I convert YAML to JSON? Yes. Once your YAML is valid, use the Convert to JSON button to get the equivalent JSON, or use the dedicated JSON ↔ YAML Converter for two-way conversion.

Use Format to clean up indentation for readability.

Use Validate before committing a config file to catch errors early.

Related Tools

CONVERTJSON ↔ YAML FORMATJSON Formatter VIEWJSON Viewer