YAML Formatter & Validator
Beautify, minify, and validate YAML online
What is YAML Formatter?
YAML Formatter is a free online tool to beautify, minify, and validate YAML documents. YAML (YAML Ain't Markup Language) is a human-friendly data serialization format widely used for configuration files (Docker Compose, Kubernetes, GitHub Actions, etc.). This tool helps you quickly fix indentation, check for syntax errors, and produce clean YAML output.
How to Use YAML Formatter
- Paste your YAML into the input area on the left
- Choose a mode: Format (beautify), Minify, or Validate
- For Format mode, select your preferred indentation (2 or 4 spaces)
- Copy the formatted output with the Copy button
Features
- Format / Beautify YAML with consistent indentation
- Minify YAML to compact JSON-like representation
- Validate YAML syntax with clear error messages
- Configurable indent size (2 or 4 spaces)
- Instant real-time processing
- 100% client-side — your data never leaves your browser
Frequently Asked Questions
What is YAML used for?
YAML is widely used for configuration files in DevOps and development workflows — Docker Compose (docker-compose.yml), Kubernetes manifests, GitHub Actions (.github/workflows/), Ansible playbooks, and more.
What's the difference between YAML and JSON?
Both formats represent the same data structures, but YAML uses indentation instead of braces and brackets. YAML supports comments (starting with #), multi-line strings, and is generally more readable for humans. JSON is stricter and more widely supported in APIs.
Why does YAML indentation matter?
YAML uses indentation to define structure (similar to Python). Inconsistent indentation causes parse errors. The formatter normalizes all indentation to your chosen size, which is a common fix for broken YAML files.
Is my YAML data safe?
Yes. All processing happens entirely in your browser using the js-yaml library. Your data is never sent to any server.