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YAML Formatter & Validator

Format and validate YAML configuration files. Get syntax highlighting for keys, values, comments and booleans, plus instant error detection.

Input
Output
Ready — paste your input and click Format
Try a sample: Docker Compose GitHub Actions App Config Kubernetes
📊 Stats
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Lines
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Keys
—
Comments
—
Size
⌨️ Shortcuts
Ctrl+EnterFormat YAML
Ctrl+Shift+CCopy output
Ctrl+LClear all
TabInsert indent in editor
💡 Tips
📐
Indentation matters — YAML uses spaces (not tabs) for indentation. Inconsistent indentation causes parse errors.
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Strings — most strings don't need quotes, but quote values starting with special chars like :, #, or @.
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Comments — use # for comments. They are ignored by parsers but help document your config.
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100% private — all processing runs in your browser. Nothing is uploaded.
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What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format widely used for configuration files. It's the default format for Docker Compose, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks, and many other DevOps tools. Unlike JSON, YAML supports comments and is designed to be written and read by humans.

YAML vs JSON vs XML

  • YAML is the most human-readable — great for config files edited by hand
  • JSON is strict and widely supported — great for APIs and data interchange
  • XML is verbose but supports schemas and namespaces — great for enterprise systems
  • YAML is a superset of JSON — valid JSON is also valid YAML

Frequently Asked Questions

YAML uses spaces (never tabs) for indentation, and indentation levels must be consistent. The most common error is mixing tabs and spaces. Set your editor to insert spaces and use 2 spaces per indent level for YAML files.
Most strings don't need quotes. However, you should quote values that start with special characters like :, #, @, !, >, |, or values that look like numbers (123) or booleans (true, false, yes, no) but should be treated as strings.
In YAML, a colon must be followed by a space to be treated as a key-value separator. A colon without a space (like in a URL https://...) is treated as part of the string, not a key-value pair.
Done!

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About This YAML Formatter & Validator

Writing clean, consistently indented code is essential for readability and maintainability — but manually formatting YAML Validator can be tedious and error-prone. This free online YAML Formatter & Validator instantly reformats your raw or minified YAML Validator into properly indented, human-readable code with just one click.

How to use

  1. Paste your YAML Validator code into the input box on the left.
  2. Click Format (or press Ctrl+Enter).
  3. Copy the formatted output from the right panel.

Why use this tool?

This tool is especially useful for developers working with API responses, debugging production builds, or reviewing third-party YAML Validator code.

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Frequently Asked Questions

Is this YAML Formatter & Validator free to use? +
Yes, completely free. No signup, no account, no payment required. Just paste your input and use it directly in your browser.
Does this tool store or send my data anywhere? +
No. Everything runs entirely in your browser using JavaScript. Your data never leaves your device or gets sent to any server.
What browsers does this tool support? +
It works in all modern browsers — Chrome, Firefox, Safari, Edge, and Opera — on both desktop and mobile.
Can I use this tool offline? +
Once the page is loaded, the tool runs locally in your browser without needing an active internet connection for most operations.
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Custom Development

Need a Custom Version of This Tool?

This YAML Formatter & Validator works for most use cases — but if you need batch processing, API access, private hosting on your own domain, or a completely bespoke tool built around your workflow, I can build it.

Request Custom Build → Typical turnaround: 3–7 days