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Your files never leave your device. Built for developers who value privacy.

  1. Toolkernel
  2. /
  3. YAML Tools
  4. /
  5. Formatter

YAML Formatter & Converter

Format, validate, and convert YAML - 100% in your browser

100% Private

YAML Input

Format Options

Formatted YAML

How to Use This YAML Formatter

1

Choose Mode

Format, YAML→JSON, JSON→YAML, or Compare

2

Paste Content

Paste your YAML or JSON input

3

Set Options

Indent, quotes, sort keys

4

Copy Result

Copy formatted output

What This Formatter Does

Format & Beautify

Standardize indentation (2, 4, or 8 spaces), quote style, and key ordering across your YAML configs.

Validate Syntax

Real-time validation with clear error messages and line numbers to help you debug YAML issues.

Convert Formats

Losslessly convert between YAML and JSON. Useful for APIs or debugging complex structures.

Compare Files

Side-by-side diff with added (green), removed (red), and changed (yellow) values highlighted.

Troubleshooting YAML Errors

Indentation Error

"bad indentation" or "expected <block end>"

Solution: Use consistent spaces (not tabs). All items at the same level must have the same indentation. Child items must be indented more than parents.

Missing Space After Colon

"mapping values are not allowed here"

Solution: YAML requires a space after colons. Use key: value not key:value.

Special Characters

"could not find expected ':'" or unexpected characters

Solution: Quote strings containing special characters like :, @, #, *, &. Use 'single quotes' or "double quotes".

Formatting Options Explained

OptionDescriptionWhen to Use
Indent (2/4/8)Number of spaces for each nesting level2 is standard for K8s; 4 for readability
Quote StyleSingle (') or double (") quotes for stringsSingle is common; double for special chars
Sort KeysAlphabetically order all keysFor consistent, diff-friendly output
Force QuotesQuote all string valuesWhen values might be misinterpreted

Your Config Files Stay Private

This formatter runs entirely in your browser. Your YAML configs—including Kubernetes secrets, database credentials, and API keys—are never sent to any server. Verify by checking your browser's Network tab, or use the tool offline after loading.

Frequently Asked Questions

How do I convert YAML to JSON?

Click 'YAML → JSON', paste your YAML, and click 'Convert to JSON'. The output appears instantly. Useful for APIs or debugging.

How do I convert JSON to YAML?

Click 'JSON → YAML', paste your JSON, choose formatting options, and click 'Convert to YAML'. Great for creating K8s manifests from JSON.

Why is my YAML invalid?

Common issues: mixing tabs/spaces, missing space after colons, unquoted special characters. The error shows the line number to help debug.

Is my data secure?

Yes. All processing happens in your browser. Your configs never leave your device. You can even use this offline after the page loads.

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