Free YAML Formatter & Validator
Format, beautify, and validate YAML documents with real-time syntax error checking. Free, fast, and works entirely in your browser with no sign-up required.
YAML Formatter
Format, lint, and validate YAML documents. Convert between YAML and JSON with multi-document support.
Load YAML
Input
Output
Formatted output will appear here
Paste YAML, upload a file, or try a sample
YAML Linting
About YAML Formatter
Format & Beautify
Transform YAML into a clean, readable format with customizable indentation (2/4/tabs), line width, and flow styles.
Syntax Highlighting
Color-coded output distinguishes keys, values, comments, anchors, and different data types at a glance. JSON output is also highlighted.
Tree View & Search
Explore your YAML as a collapsible tree with search filtering. Click any node to get its dot-notation path.
YAML Linting
Check for common issues like trailing spaces, duplicate keys, inconsistent indentation, and more.
Multi-Document
Handle YAML files with multiple documents separated by --- delimiters with per-document statistics.
JSON Conversion
Convert between YAML and JSON formats in both directions with proper formatting and minification.
Drag & Drop Upload
Upload .yml/.yaml files by clicking or dragging and dropping directly onto the input area. Save work to local history.
Diff View
Compare your original input with the formatted output using a line-by-line diff view with added/removed highlighting.
Keyboard Shortcuts
Format, minify, and convert with keyboard shortcuts. Press Ctrl/Cmd+K to see all available shortcuts.
Frequently Asked Questions
What is the YAML Formatter?
The YAML Formatter is a free online tool that formats, beautifies, and validates YAML documents to ensure proper structure and syntax.
Is the YAML Formatter free?
Yes, it is completely free with no registration required. All formatting happens client-side in your browser.
Does it validate YAML syntax?
Yes, the YAML Formatter checks your YAML for syntax errors and provides clear error messages to help you fix any issues.
Is my data safe with this tool?
Absolutely. The YAML Formatter & Validator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.
Does the YAML Formatter & Validator work on mobile devices?
Yes, the YAML Formatter & Validator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.
Do I need to create an account to use this tool?
No account or registration is needed. Simply open the YAML Formatter & Validator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.
How do I use the YAML Formatter & Validator?
Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.
Which browsers are supported?
The YAML Formatter & Validator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.
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About Free YAML Formatter & Validator
Free YAML Formatter & Validator is a free, browser-based tool in our Code Tools collection. Everything runs locally on your device — no uploads, no sign-up, and your data stays private.