YAML validator and formatter

Validate, repair, format and compare YAML online, catch values that YAML 1.1 tools misread, validate against a JSON Schema and convert YAML to JSON.

Features

• Validate YAML, including multi-document files, with every error reported by line and column
• Detect duplicate keys, tab indentation and alias bombs
• Flag values that YAML 1.1 tools read differently (yes/no/on/off, 0755, 1.10, 22:22) and quote them in one click
• Auto-repair broken YAML: tab indentation, missing spaces after colons, unquoted special values, unclosed quotes and brackets, misaligned keys
• Beautify YAML with 2- or 4-space indentation and optional key sorting while keeping comments, or minify it to flow style
• Expand anchors, aliases and merge keys
• Validate YAML data against a JSON Schema
• Compare two YAML documents side by side by their data, ignoring comments, formatting and key order
• Convert YAML to JSON and JSON to YAML

Everything runs entirely in your browser — nothing you paste is sent to a server.