How to Format and Validate YAML
YAML is the configuration language of modern DevOps — Kubernetes manifests, Docker Compose files, GitHub Actions workflows, and CI/CD pipelines all use YAML. Its indentation-based syntax is clean but unforgiving — a single misplaced space can break an entire deployment. Formatting and validating YAML before deploying catches these errors early.
- Format messy YAML into clean, indented output.
- Covers common yaml errors.
- Covers formatting yaml.
- Covers yaml vs json for configuration.
- Covers converting yaml to json.
Common YAML Errors
Inconsistent indentation (mixing tabs and spaces — YAML requires spaces only). Wrong indentation level (a 2-space indent where 4 was expected). Missing colon after a key. Unquoted strings that look like other types ('yes' is parsed as boolean true, '3.0' as a number). Multi-line strings without proper block scalar indicators (| or >).
Formatting YAML
The YAML Formatter normalizes indentation (consistently 2-space), aligns keys, and fixes spacing issues. Paste messy YAML — copied from logs, documentation, or Stack Overflow — and get clean, consistently indented output. The tool also validates syntax and highlights errors with line numbers.
YAML vs JSON for Configuration
YAML supports comments (# comment), multi-line strings, anchors and aliases (reusable values), and more readable syntax for deeply nested structures. JSON is stricter and more universally supported but doesn't allow comments and is more verbose. Many tools accept both — use YAML for human-edited configuration and JSON for machine-generated data.
background-size animation or @property registered custom properties instead.Converting YAML to JSON
The YAML-JSON Converter translates between formats in both directions. This is useful when a tool requires JSON but you prefer writing in YAML, or when you need to validate YAML by converting to JSON and checking the structure. Both tools process everything locally in your browser.