YAML Formatter & Beautifier

YAML Formatter & Beautifier

Format and beautify YAML files with consistent indentation, configurable quoting, and key sorting. Paste your YAML content and instantly see properly formatted output with validation, error highlighting, and statistics. Export as JSON, TOML, or Properties format.

使い方

Paste your YAML content into the input area. The formatter processes it instantly with your chosen options: indent size (2 or 4 spaces), quote style (auto, double, single, or bare), alphabetical key sorting, array style (block or flow), and line width. View validation results with error line numbers. Copy the formatted output or download as .yaml or .yml file. Convert to JSON, TOML, or Properties format with one click.

特徴

• Consistent Indentation — Normalize YAML indentation to 2 or 4 spaces throughout the entire document. Fixes mixed indentation and alignment issues.
• Quote Style Control — Auto-quote only when needed, always use double or single quotes for strings, or remove unnecessary quotes. Handles the YAML quoting rules correctly.
• キーの並べ替え — Optionally sort keys alphabetically within each nesting level for consistent, organized configuration files.
• Array Style — Choose between block style (each item on a new line with -) or flow/inline style ([item1, item2]) for short arrays.
• 検証 — Detects invalid YAML with error messages and line numbers. Shows document statistics: total keys, max nesting depth, array count, total lines.
• Export Formats — Convert YAML to JSON, TOML (best effort), or Properties (flat key=value with dot notation for nesting). Each with copy button.
• 追加オプション — Collapse empty collections, set line width for wrapping, strip comments, trim trailing whitespace.
• クイックリファレンス — Collapsible YAML syntax guide covering common gotchas (Norway problem: NO → false), indentation rules, and multi-line string styles (| literal, > folded).

YAML Syntax

YAML uses indentation to represent nesting (spaces only, never tabs). Keys and values are separated by colons: key: value. Arrays use dashes: - item. Strings can be bare, single-quoted, or double-quoted. Multi-line strings use | (literal, preserves newlines) or > (folded, joins lines). Comments start with #. YAML is commonly used in Docker Compose, Kubernetes, GitHub Actions, Ansible, and many configuration files.