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YAML Formatter

Format and validate YAML data instantly in your browser.

YAML formattingIndentation checksLocal text processingUpdated May 2026

Validation

Valid YAML

Input lines

21

Output lines

21

Indent size

2 spaces

Mode

Format

Dynamic Formatting Insights

Your YAML is valid and formatted with 2-space indentation.
Trailing whitespace cleanup is enabled.
Line endings are normalized to LF.
Comments are preserved where supported by the YAML parser.
Anchors, aliases, custom tags, and multiline strings may need manual review after formatting.

How YAML Formatting Works

YAML formatting makes indentation and structure easier to read.

YAML uses indentation instead of braces to show nesting.

Validation checks whether the YAML can be parsed safely as data.

Advanced YAML features such as anchors, aliases, tags, and multiline strings need careful review.

YAML Syntax and Indentation Explained

YAML uses spaces, not tabs.
Key-value pairs use key: value.
Lists usually use a dash.
Nested data must align consistently.
Strings sometimes need quotes.
Multiline strings use | or >.
Comments start with #.
Anchors and aliases reuse values.

Common YAML Errors Explained

Inconsistent indentation
Tabs instead of spaces
Missing colon after a key
Duplicate keys
Unquoted special values
Invalid list indentation
Broken multiline strings
Unexpected characters
Comments or anchors lost during rebuilding

Config, DevOps, and API Use Cases

Cleaning configuration files
Formatting Docker Compose-style YAML
Formatting Kubernetes-style YAML
Checking CI/CD pipeline config
Preparing API examples
Formatting documentation snippets
Reviewing settings files
Cleaning copied YAML from docs
Validating config before committing changes

This formatter validates YAML syntax only. It does not perform Kubernetes, Docker Compose, GitHub Actions, or CI/CD schema validation.

Common YAML Formatting Examples

Simple key-value YAML

name: BlinkCalc

Nested object indentation

app:
  name: BlinkCalc
  enabled: true

Array/list formatting

features:
  - calculators
  - converters

Multiline string

description: |
  First line
  Second line

Comment handling

# Comments are preserved when possible.

Trailing spaces

Trailing spaces can be removed automatically.

Validation error

Bad indentation often reports a line and column.

JSON-like YAML

{ name: BlinkCalc, active: true } can be formatted as readable YAML.

Privacy and Local Processing Notes

Pasted YAML is processed locally in your browser.

No account is required and no backend storage should be added.

Downloaded YAML is generated locally from the browser.

YAML content is parsed as data, not executed as code.

Avoid pasting sensitive production secrets unless necessary.

This tool is intended for lightweight formatting, validation, and cleanup.

Method Explanation

  1. 1Paste YAML into the input area.
  2. 2Validate the YAML syntax safely.
  3. 3Apply selected formatting options such as indentation and whitespace cleanup.
  4. 4Preserve comments and advanced features only if the formatter supports them.
  5. 5Show validation errors with line and column details where possible.
  6. 6Preview the formatted YAML.
  7. 7Copy or download the result.

Frequently Asked Questions

A YAML formatter cleans and structures YAML so indentation, lists, nested objects, and configuration blocks are easier to read.

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