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YAML Validator – Check Syntax & Structure for Config Files

Validate YAML/YML syntax, indentation, anchors, and references for Docker, Kubernetes, and config management workflows with instant diagnostics.

🟢 Runs locally · no uploads
YAML Input
name: Project version: 1.0.0 author: John Doe dependencies: - react - typescript
Result
Click Validate to check...

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› About this tool · FAQ

Validate YAML syntax online with comprehensive error checking, indentation validation, and structure analysis. Free YAML validator for configuration files, Docker Compose, Kubernetes manifests, and more.

How do I validate YAML syntax online?

Simply paste your YAML content into the validator, and it will instantly check for syntax errors, indentation issues, and structural problems. No installation required - everything runs in your browser.

What YAML features does the validator support?

The validator supports YAML 1.2 features including scalars, sequences, mappings, anchors, references, comments, and multi-document files.

How does indentation validation work?

The validator checks for consistent indentation, detects mixed tabs and spaces, and ensures proper nesting levels according to YAML standards.

Can it detect duplicate keys?

Yes, the validator can detect and flag duplicate keys within the same mapping, which is invalid in YAML and can cause parsing errors.

What is the difference between block and flow style?

Block style uses indentation and newlines (typical YAML), while flow style uses brackets and braces (similar to JSON). Both are valid YAML formats.

Does it validate data types?

The validator checks basic data type syntax and can identify strings, numbers, booleans, nulls, arrays, and objects in your YAML document.