About YAML Formatter
A fast, modern alternative to dated YAML tools — built for developers who need to format, validate, and convert YAML without any friction.
What it does
Format & Beautify
Consistently indents and structures your YAML with configurable indentation (2, 4, or 8 spaces).
Real-time Validation
Validates as you type with human-readable error messages that pinpoint the exact line with the problem.
YAML ↔ JSON Conversion
Convert between YAML and JSON instantly. Auto-detects the input format so you never have to choose manually.
Multi-Document Support
Handles YAML files with multiple documents separated by --- and validates each one independently.
Privacy commitment
Your YAML never leaves your browser
All processing — formatting, validation, and conversion — happens 100% client-side in your browser using JavaScript. We have no server that receives your data. No API calls are made with your content. Once the page loads, every feature works entirely offline. We do not collect, store, log, or transmit your YAML or JSON content in any form.
Tech stack
Built with Next.js and Tailwind CSS. The editor is powered by CodeMirror 6 with full YAML syntax highlighting. YAML parsing and serialization use the js-yaml library. Deployed on Vercel.