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    YAML Formatter and Beautifier

    Paste your YAML to format, beautify and validate it. Everything runs in your browser.

    Input YAML

    Paste your YAML content here

    Formatted Output

    Beautified and validated YAML

    About YAML Formatter

    This free online YAML formatter and validator cleans up messy configuration files. Use it on Kubernetes manifests, Docker Compose files, Ansible playbooks or any other YAML-based configuration: it fixes indentation, validates syntax, and catches common errors before they cause production issues.

    How the YAML formatter works: paste YAML, it is parsed and validated in your browser, valid input comes back with fixed indentation, invalid input returns an error message that shows what to fix

    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, so your configuration files never touch our servers
    • Copy-Paste Ready: Copy the result to your clipboard with one click
    • Error Messages: Clear error messages that show what to fix

    Common YAML use cases

    YAML is the most common configuration language in modern infrastructure. You will see it most often in these places:

    • 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

    These are the most frequent YAML syntax errors and their fixes:

    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, so 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 is 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. JSON works well for APIs and data interchange, but YAML is easier to read, which suits configuration files that people write and maintain regularly.

    Using it in your workflow

    Run the formatter before committing configuration changes to version control, when validating configurations pulled from team members, when cleaning up auto-generated manifests from Helm or Kustomize, or when preparing configuration files for production deployment. Instant validation saves time by catching errors before they reach your CI/CD pipeline or production environment.