utilAZ Logo

YAML Prettify

Format and beautify YAML files with proper indentation

Formatting Options

YAML Formatting Tips

  • Real-time Processing: YAML is formatted automatically as you type
  • Indentation: YAML uses spaces for indentation, never tabs
  • File Support: Drag and drop .yaml or .yml files for instant formatting
  • Error Detection: Line-specific error messages help you fix syntax issues
  • Always validate YAML syntax before deploying to production

About YAML File Formatting

YAML (YAML Ain't Markup Language) formatting transforms poorly structured YAML files into well-organized, human-readable configuration files with proper indentation and structure. Essential for DevOps, configuration management, and data serialization tasks.

  • Proper indentation and structure alignment
  • Comment preservation and formatting
  • Array and object organization
  • YAML syntax validation and error detection
  • Multi-document support and separation

YAML Formatting Features

Structure Enhancement

  • Consistent indentation levels (2 or 4 spaces)
  • Proper key-value pair alignment
  • Array and list formatting
  • Nested object organization
  • Multi-line string handling

Style Options

  • Configurable indentation width
  • Array style (block or flow)
  • Quote handling preferences
  • Line length optimization
  • Comment alignment and spacing

Frequently Asked Questions

How to format YAML online?

Paste your YAML content into the utilAZ YAML Prettify tool and it will instantly reformat it with consistent indentation and proper structure. The tool runs entirely in your browser, requires no sign-up, and never uploads your data to a server.

What is a YAML beautifier?

A YAML beautifier is a tool that takes messy or inconsistently indented YAML and rewrites it with uniform spacing and alignment. It does not change the underlying data structure. utilAZ provides a free online YAML beautifier that handles nested objects, arrays, and multi-line strings correctly.

How to prettify YAML in VS Code?

Install the YAML extension by Red Hat from the VS Code marketplace, then use the Format Document command (Shift+Alt+F on Windows or Shift+Option+F on Mac). For a quick one-off format without extensions, paste your YAML into the utilAZ online formatter instead.

Best free YAML formatter?

utilAZ offers a free YAML formatter with configurable indentation, syntax validation, and error highlighting. It works client-side in any modern browser, requires no account, and supports large files, making it ideal for DevOps engineers and developers.

How to fix YAML indentation?

Paste your broken YAML into the utilAZ YAML Prettify tool and it will automatically correct indentation levels throughout the document. YAML relies on consistent spaces for structure, so even one misaligned line can cause parse errors that this tool resolves instantly.

Does YAML have a formatter?

YAML itself is a data format and does not include a built-in formatter, but many tools exist to format it. You can use online tools like utilAZ, CLI utilities like yq, or editor extensions. The utilAZ YAML Prettify tool is free and works directly in your browser.

How YAML Formatting Works

YAML formatting parses your document, normalizes indentation, and re-serializes it with consistent spacing. Because YAML relies on whitespace for structure, even small alignment errors can change meaning or cause parse failures.

1. Parse

The raw text is tokenized into mappings, sequences, and scalars. Syntax errors surface immediately at this stage.

2. Normalize

Indentation is standardized to your chosen width (2 or 4 spaces). Flow collections like [a, b] can be expanded to block style.

3. Serialize

The tree is written back with consistent spacing. Literal (|) and folded (>) blocks are preserved exactly.

YAML Formatting Styles

Different ecosystems favor different indent widths and conventions. Our formatter adapts to each.

Kubernetes / Helm (2-space)

The standard for K8s manifests and Helm charts. Lists are indented under their parent key with a leading dash.

Used by: kubectl, kustomize, Helm, ArgoCD
GitHub Actions / GitLab CI (2-4 space)

CI/CD pipelines where jobs, steps, and triggers are deeply nested. Wider indent can improve readability.

Used by: GitHub Actions, GitLab CI, Azure Pipelines
Docker Compose

Service definitions with environment variables, volumes, and networks. Consistent 2-space indent is standard.

Used by: docker compose, Podman, Swarm
Ansible Playbooks

Task lists and role variables benefit from block-style formatting with clear nesting for each play and handler.

Used by: Ansible, AWX, Molecule

Advanced YAML Features

The formatter preserves all YAML-specific constructs while normalizing surrounding whitespace.

Multi-line Strings

Literal blocks (|) preserve every newline. Folded blocks (>) join lines into paragraphs. Both are kept as-is during formatting.

Anchors and Aliases

&anchor and *alias references are preserved so you can reuse shared configuration blocks without duplication.

Comments

Inline and full-line # comments are retained and indented to match their surrounding context for clarity.

Flow vs. Block Style

Compact flow notation {key: val} and [a, b] can be expanded to block style for better readability in diffs.

YAML Formatting Best Practices

  • Consistent Indentation: Always use spaces, never tabs. Stick to 2 or 4 spaces consistently
  • Meaningful Comments: Add comments to explain complex configurations and sections
  • Quote When Needed: Quote strings with special characters, numbers as strings, or when ambiguous
  • Logical Grouping: Group related configuration items together with blank lines
  • Array Style Consistency: Choose block or flow style for arrays and use consistently
  • Key Ordering: Order keys logically (required first, optional after) for better readability
  • Line Length: Keep lines under 120 characters for better code review experience

Formatting YAML in Code

After validating with our online tool, you can automate YAML formatting in your projects using popular libraries.

Quick Reference by Language:

JavaScript: yaml.dump(yaml.load(str), { indent: 2, lineWidth: 120 })
Python: yaml.dump(yaml.safe_load(s), default_flow_style=False, indent=2)
Go: yaml.Marshal(data) // gopkg.in/yaml.v3
CLI (yq): yq eval '.' input.yaml > formatted.yaml

Our browser-based formatter requires no installation and processes everything locally for privacy.

YAML Formatting Applications

DevOps & Infrastructure:
  • Kubernetes manifests
  • Docker Compose files
  • Ansible playbooks
  • Helm charts
CI/CD Pipelines:
  • GitHub Actions
  • GitLab CI
  • Azure DevOps
  • Jenkins pipelines
Configuration Files:
  • Application configs
  • API specifications (OpenAPI)
  • Static site generators
  • Documentation sites
Data Formats:
  • Data serialization
  • Configuration templates
  • Localization files
  • Test data fixtures

Common Use Cases

  • Kubernetes deployment configuration
  • CI/CD pipeline definition files
  • Docker Compose service definitions
  • Ansible automation playbooks
  • Application configuration management
  • API documentation (OpenAPI/Swagger)
  • Static site generator configs
  • Infrastructure as Code templates