Online YAML Validator & Linter

Why Use an Online YAML Validator?

YAML is an indent-sensitive format, meaning that a single mismatch in spaces will render a file completely unparseable. Traditional text editors do not always show whitespace inconsistencies, leading to mysterious failures during deployments.

An online YAML validator acts as a quality gate. By validating configurations inside your browser, you catch errors before committing files to Git or pushing changes to staging environments. Best of all, because this parser executes client-side, your API keys and configuration settings are never exposed online.

How the YAML Syntax Checker Works

Our validator utilizes a highly accurate AST parser that matches the official YAML 1.2 specification:

1. Real-time Linting: The editor reads your keystrokes and runs syntax validations on every change, avoiding lag.
2. Error Line Highlighting: If a syntax violation is found, it squiggles the offending line red and details the line and column offset in the report.
3. One-Click Debugging: If you spot an error, simply adjust the indentations, and the indicator will turn green as soon as the syntax is corrected.

Standard YAML Validation Rules

Keep these rules in mind to write valid YAML files:

• Indent with Spaces: Standard YAML configurations use 2 spaces per indentation level. Do not mix 2 and 4 spaces in parent-child trees.
• Document Boundaries: If combining multiple documents in a single file, separate them using three dashes (---) at the start and three dots (...) at the end.
• Key Spacing: Always leave a space after a colon. Writing port:8080 will throw an error; instead, write port: 8080.
• List Indicators: Bullet points representing items in an array must use a hyphen followed by a space (e.g., - item).

Frequently Asked Questions