What's the difference between YAML 1.1 and 1.2?

YAML 1.2 aligns with JSON and tightens a few rules — most notably, it no longer treats values like 'yes', 'no', 'on', and 'off' as booleans. YAML 1.1 does. Choosing the right version ensures the tool parses your document the way your runtime will.

Why does my YAML fail to parse?

The most common causes are inconsistent indentation, tabs used instead of spaces, or unquoted values that contain special characters like colons. The validator points to where the structure breaks so you can fix it.

What does JSON Schema validation add?

Syntax validation confirms the YAML is well-formed; JSON Schema validation confirms the content has the right fields, types, and structure. It catches mistakes like a missing required key or a string where a number was expected.

How does the tool handle anchors and aliases?

It resolves YAML anchors (&) and aliases (*) when parsing, so the formatted output reflects the fully expanded structure while keeping the document valid.

Is my YAML sent to a server?

No. All parsing, formatting, and validation happen in your browser, so your documents — including any secrets or internal values — are never uploaded or stored.

YAML Formatter · Beautifier · Validator

Format, beautify, minify, and validate YAML online. Supports YAML 1.1 and 1.2, multi-document files, JSON Schema validation, key sorting, and anchor/alias handling.

Options

Configure YAML formatting and validation settings

YAML Version

Action Buttons

Indentation

Flow Style

Line Width

Sort Keys

Off

Keep Anchors

Resolve Aliases

Off

Preserve Comments

Off

Schema Validation

Off

Input

Paste your YAML here (Cmd/Ctrl+Enter to format)

Output

Formatted output will appear here

Quick Guide

YAML Versions

1.2 (default): Latest YAML specification with improved parsing
1.1: Legacy version for compatibility with older systems

Actions

Format: Pretty-print YAML with proper indentation and structure
Minify: Remove unnecessary whitespace for compact output
Validate: Check syntax and optionally validate against JSON Schema

Features

Sort Keys: Alphabetically sort object keys for consistent output
Keep Anchors: Preserve YAML anchors (&) and aliases (*)
Resolve Aliases: Expand aliases into concrete data (no anchors in output)
Multi-document: Support for files with multiple YAML documents (---)
Schema Validation: Validate YAML structure against JSON Schema

About YAML Formatter · Beautifier · Validator

YAML is forgiving to write and unforgiving to debug. A single mis-indented line, a tab where spaces were expected, or an ambiguous value can break a CI pipeline or a Kubernetes manifest in ways the error message rarely explains. A formatter that parses the document the same way your tooling does turns guesswork into a clear pass or fail.

This tool formats, beautifies, and minifies YAML with deterministic output, so the same input always produces the same result — ideal for diffs and version control. It validates against both YAML 1.1 and 1.2, handles multi-document files, resolves anchors and aliases, and can sort keys and normalize indentation and line width to whatever your style guide requires.

If you work with JSON Schema, you can validate the document's structure as well as its syntax, catching missing or mistyped fields before they reach production. Parsing and formatting run entirely in your browser, so config files — including ones with secrets or internal hostnames — never leave your machine.

How to use YAML Formatter · Beautifier · Validator

Paste your YAML
Drop your YAML document into the input area. Single documents and multi-document files separated by --- both work.
Choose your options
Set the indentation, line width, and whether to sort keys. Pick the YAML version (1.1 or 1.2) that matches your tooling.
Format or validate
Beautify for readable output, minify to compact it, or validate to check the syntax — and optionally a JSON Schema — without changing the content.
Copy the result
Review the formatted output and any validation messages, then copy the clean YAML back into your project.

Frequently asked questions

YAML ⇄ JSON Converter

Instantly convert data between YAML and JSON formats with real-time updates and syntax highlighting.

JSON Formatter · Beautifier · Validator

Format, minify, sort keys, and validate JSON/JSONC/JSON5 with optional JSON Schema validation. Supports comments and trailing commas.

JSON to TypeScript Converter

Instantly convert JSON objects or arrays into clean TypeScript interfaces or type aliases.