YAML Formatter
Developer Tools
Format YAML into clean, readable indentation and check for syntax errors online. Paste YAML, format it instantly, and copy the result.
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How to Use YAML Formatter
Use the controls above, then check the example and limitations below.
Paste YAML Input
Paste or type your raw YAML document into the input textarea.
Select Indentation & Format
Choose your preferred indentation (2 or 4 spaces; 2 spaces is a common convention for many YAML configuration files) and click 'Format YAML'.
Copy or Download Formatted YAML
Review the formatted output or any syntax error coordinates, then click 'Copy Output' or 'Download .yaml'.
What is YAML Formatter & How Does It Work?
The YAML Formatter formats, indents, and checks syntax for YAML (YAML Ain't Markup Language) documents directly in your browser. It reorganizes valid YAML into uniform indentation while preserving comments (#), original anchor names, block scalar formatting, and key order.
YAML structure relies on consistent space indentation rather than brackets or closing tags. This tool parses the document into a syntax tree to format indentation cleanly (2 or 4 spaces) and checks for syntax errors. Syntax checking confirms that the input follows YAML grammar rules; it does not validate application-specific schemas such as Kubernetes manifests, Docker Compose files, GitHub Actions workflows, or OpenAPI specifications.
This YAML formatting runs locally in your browser with zero server transmission, keeping your configuration files and manifests on your local device.
YAML Indentation & Syntax Rules
Indentation = Spaces Only (No Tabs) | Structure = Key-Value Mappings & Hyphenated ListsYAML relies on consistent space indentation to establish hierarchy and scoping. Tabs are not allowed for YAML indentation under the YAML specification. 2 spaces is a common convention for many YAML configuration files. Colons denoting key-value pairs must be followed by a space, and list items begin with a hyphen followed by a space.
Step-by-Step Worked Example:
# Application configuration
app:
name: PixelTools
enabled: true
ports:
- 3000
- 8080
defaults: &defaults
retries: 3
api:
<<: *defaults
endpoint: /v1
description: |
Line one
Line twoKey Features & Benefits
Structure & Comment Preservation
Parses YAML via a document syntax tree, preserving header and inline comments (#), author anchor names, block scalars (| and >), and key order where supported. Formatting preserves document structure, though some scalar representations may be normalized by the YAML parser.
Configurable Space Indentation
Format indentation with 2 spaces or 4 spaces. 2 spaces is a common convention for many YAML configuration files.
Exact Syntax Error Coordinates
Reports syntax errors with exact line and column numbers alongside a safe code snippet to help locate indentation mistakes quickly.
Tab Indentation Detection
Identifies tab characters in indentation and pinpoints the line and column, as tabs are not allowed for YAML indentation.
Local Browser Execution
This YAML formatting runs locally in your browser with zero network transmission, keeping configuration data secure on your device.
Common Use Cases
Kubernetes Manifest Formatting
Format Deployment, Service, and ConfigMap YAML files for readable indentation before applying them with kubectl. (Syntax checking verifies YAML grammar, not Kubernetes API schemas.)
CI/CD Pipeline Configurations
Format .github/workflows and GitLab CI configuration files to catch indentation errors and illegal tabs early. (CI workflow schemas are not validated.)
Docker Compose Files
Maintain clean, readable indentation across multi-service docker-compose.yml configuration files.
Frequently asked questions
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