Mr.PlanB Logo

    YAML Formatter

    Beautify and validate your YAML configuration files.

    Input YAML

    Paste your YAML content here

    Formatted Output

    Beautified and validated YAML

    About YAML Formatter

    This free online YAML formatter and validator helps you clean up messy configuration files with professional-grade formatting. Whether you're working with Kubernetes manifests, Docker Compose files, Ansible playbooks, or any YAML-based configuration, this tool ensures proper indentation, validates syntax, and catches common errors before they cause production issues.

    Features

    • Instant Validation: Catches syntax errors like missing colons, incorrect indentation, and invalid characters
    • Smart Formatting: Automatically fixes indentation and spacing issues while preserving your data structure
    • Privacy Focused: All processing happens in your browser - your configuration files never touch our servers
    • Copy-Paste Ready: One-click copy to clipboard for quick integration into your workflow
    • Error Messages: Clear, actionable error messages that help you fix issues quickly

    Common YAML Use Cases

    YAML is the configuration language of choice for modern infrastructure. Here's where you'll encounter it most:

    • Kubernetes: Deployments, Services, ConfigMaps, Secrets, and custom resource definitions
    • Docker Compose: Multi-container application definitions with networks, volumes, and dependencies
    • Ansible: Playbooks for configuration management and automation workflows
    • CI/CD Pipelines: GitHub Actions, GitLab CI, CircleCI, and Jenkins pipeline definitions
    • Infrastructure as Code: Configuration files for Terraform, AWS CloudFormation, and Azure Resource Manager
    • Proxmox: Cloud-init templates and automation scripts

    YAML Best Practices

    Follow these guidelines to write maintainable YAML configurations:

    • Consistent Indentation: Always use 2 spaces (not tabs) for indentation throughout your files
    • Quote Strings: Use quotes around strings that contain special characters or start with numbers
    • Anchors and Aliases: Use YAML anchors (&) and aliases (*) to avoid repetition in large files
    • Comments: Document complex configurations with # comments for future maintainers
    • Validation Before Deployment: Always validate YAML files before applying them to production systems
    • Multi-line Strings: Use | for literal blocks and > for folded blocks when working with long text

    Common YAML Errors and Fixes

    Here are the most frequent YAML syntax errors and how to fix them:

    Incorrect Indentation: YAML is whitespace-sensitive. Each level must use the same number of spaces.
    Missing Colon: Key-value pairs require a colon followed by a space (key: value).
    Tabs Instead of Spaces: YAML doesn't allow tabs for indentation - use spaces only.
    Unquoted Special Characters: Strings with :, {}, [], %, &, *, #, ?, |, -, <, >, =, !, %, @, ` need quotes.
    Wrong List Syntax: List items must start with a dash and space (- item).

    Why YAML Over JSON or XML?

    YAML has become the standard for infrastructure configuration because it's human-readable, supports comments, allows multi-line strings without escape characters, and has a cleaner syntax than JSON or XML. While JSON is great for APIs and data interchange, YAML's readability makes it perfect for configuration files that humans need to write and maintain regularly.

    Integration with Your Workflow

    This formatter integrates seamlessly into your development workflow. Use it before committing configuration changes to version control, validating configurations pulled from team members, cleaning up auto-generated manifests from Helm or Kustomize, or preparing configuration files for production deployment. The instant validation saves time by catching errors before they reach your CI/CD pipeline or production environment.