Formatters

YAML Formatter/Validator

Format, validate, and minify YAML files online free

YAML / JSON Input

Indent

Quote style

Null

Boolean

Schema

Wrap at

Sort keys

About

Formats, validates, and minifies YAML content with configurable indentation, key sorting, and syntax validation. Detects YAML-to-JSON conversion for programmatic use, supports multi-document YAML streams, and provides detailed error messages for malformed YAML.

YAML is widely used for configuration files (Docker Compose, Kubernetes, CI/CD pipelines) but is notoriously sensitive to indentation errors. This tool helps developers validate, format, and convert YAML without hunting for invisible whitespace bugs.

Who should use this tool?

DevOps engineers managing Kubernetes or Docker Compose configs, CI/CD pipeline maintainers, Python developers using YAML for configuration, and anyone debugging YAML formatting issues.

Common use cases

Format a poorly indented docker-compose.yml file to make it readable and consistent
Validate YAML syntax before deploying to production to catch indentation bugs early
Convert YAML to JSON for programmatic consumption in JavaScript/Python scripts
Minify YAML by removing comments and whitespace for smaller file sizes in deployment
Sort keys alphabetically to enforce consistent key ordering across team config files

How to Use

Paste or upload your YAML content into the input area

Set indent size (2 or 4 spaces) — YAML does not support tabs for indentation

Toggle validation: the tool checks for common YAML errors (mixed indentation, trailing spaces, duplicate keys)

Select output format: Formatted YAML, Minified YAML, or JSON

Enable key sorting to alphabetically order top-level keys

Click "Format" and review the output; copy or download the result

Examples

Input: 'services:  web:    image: nginx' with 2-space indent. Output: 'services:\n  web:\n    image: nginx'

Input: 'name: "hello"\ncount: 3' with sort keys. Output: 'count: 3\nname: "hello"'

Best Practices

Always validate YAML before committing to version control — indentation bugs are hard to spot visually
Use 2-space indentation consistently, the most common standard across YAML projects
Run YAML through this tool after merging PRs to catch formatting regressions
Convert to JSON when debugging YAML parsing issues — JSON's strict syntax makes errors more obvious

Common Mistakes

Using tabs instead of spaces for indentation, which causes a YAML parsing error
Inconsistent indentation depth within the same file (mixing 2-space and 4-space blocks)
Forgetting to quote strings with special characters like colons, hashes, or brackets
Assuming booleans are always lowercase; YAML accepts multiple boolean formats (yes/no, true/false, on/off)

FAQ

What YAML version does this support? YAML 1.2 with most common 1.1 features.

Can I convert YAML to JSON? Yes, the tool supports YAML-to-JSON conversion as an output option.

Does it handle multi-document YAML (--- separator)? Yes, each document is processed independently.

What about anchors and aliases? Anchors (&) and aliases (*) are preserved in formatted output but resolved in JSON conversion.

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Learning Resources

Dive deeper with our comprehensive guides and tutorials.

YAML Formatter/Validator - Beginner's Guide

5 min read

YAML Formatter/Validator Advanced Techniques

8 min read

About

Who should use this tool?

DevOps engineers managing Kubernetes or Docker Compose configs, CI/CD pipeline maintainers, Python developers using YAML for configuration, and anyone debugging YAML formatting issues.

Common use cases

Format a poorly indented docker-compose.yml file to make it readable and consistent
Validate YAML syntax before deploying to production to catch indentation bugs early
Convert YAML to JSON for programmatic consumption in JavaScript/Python scripts
Minify YAML by removing comments and whitespace for smaller file sizes in deployment
Sort keys alphabetically to enforce consistent key ordering across team config files

How to Use

Paste or upload your YAML content into the input area

Set indent size (2 or 4 spaces) — YAML does not support tabs for indentation

Toggle validation: the tool checks for common YAML errors (mixed indentation, trailing spaces, duplicate keys)

Select output format: Formatted YAML, Minified YAML, or JSON

Enable key sorting to alphabetically order top-level keys

Click "Format" and review the output; copy or download the result

Best Practices

Always validate YAML before committing to version control — indentation bugs are hard to spot visually

Use 2-space indentation consistently, the most common standard across YAML projects

Run YAML through this tool after merging PRs to catch formatting regressions

Convert to JSON when debugging YAML parsing issues — JSON's strict syntax makes errors more obvious

Common Mistakes

Using tabs instead of spaces for indentation, which causes a YAML parsing error

Inconsistent indentation depth within the same file (mixing 2-space and 4-space blocks)

Forgetting to quote strings with special characters like colons, hashes, or brackets

Assuming booleans are always lowercase; YAML accepts multiple boolean formats (yes/no, true/false, on/off)

FAQ

What YAML version does this support? YAML 1.2 with most common 1.1 features.

Can I convert YAML to JSON? Yes, the tool supports YAML-to-JSON conversion as an output option.

Does it handle multi-document YAML (--- separator)? Yes, each document is processed independently.

What about anchors and aliases? Anchors (&) and aliases (*) are preserved in formatted output but resolved in JSON conversion.

YAML Formatter/Validator

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Formatters

JSON Formatter

SQL Formatter

JavaScript Minifier/Beautifier

HTML Formatter/Validator

Popular Tools

Base64 Encoder/Decoder

JWT Decoder

URL Encoder/Decoder

Learning Resources

Share

YAML Formatter/Validator

About

Who should use this tool?

Common use cases

How to Use

Examples

Best Practices

Common Mistakes

FAQ

Related Tools

Same Category — Formatters

JSON Formatter

SQL Formatter

JavaScript Minifier/Beautifier

HTML Formatter/Validator

Popular Tools

Base64 Encoder/Decoder

JWT Decoder

URL Encoder/Decoder

Learning Resources

Share