YAML Linter

Comprehensive YAML linting with detailed error reporting and style checking. Detect indentation problems, duplicate keys, and best practice violations. Get actionable suggestions for cleaner YAML files.

Drop YAML file here or click to browse

YAML Input

Linting Options

Indentation Width

Max Line Length

Strict mode (enforce best practices)

Common YAML Linting Issues

Inconsistent indentation: Mixing 2-space and 4-space indents in the same file
Tabs vs spaces: YAML requires spaces; tabs cause parsing errors
Duplicate keys: Same key appears multiple times in an object
Trailing spaces: Whitespace at end of lines can cause issues with some parsers
Long lines: Lines exceeding recommended length hurt readability
Missing document separator: Multi-doc files should use --- between documents
Undefined anchors: Alias references anchor that doesn't exist

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Frequently Asked Questions

Validation checks basic syntax correctness, while linting enforces best practices and style rules. The linter detects issues like duplicate keys, improper indentation, inconsistent styles, and potential errors that might parse but cause problems.

The linter checks for: inconsistent indentation, tabs mixed with spaces, duplicate keys, trailing spaces, line length limits, improper anchor/alias usage, and missing document separators in multi-document files.

Yes. The linter identifies inconsistent indentation, detects tabs mixed with spaces, and flags lines where indentation doesn't match the expected depth. Each issue shows the exact line number.

Yes. Duplicate keys within the same object are flagged as errors. YAML parsers typically use the last value, but duplicates usually indicate mistakes and should be fixed.

Errors prevent YAML from being valid and will cause parsing failures. Warnings indicate style issues or potential problems that don't break syntax but should be reviewed—like very long lines or inconsistent indentation.

The tool includes configurable options for indentation width (2 or 4 spaces), maximum line length, and strictness level. You can enable or disable specific rule categories.

Yes. The linter works with any YAML file including Kubernetes manifests, Docker Compose files, GitHub Actions workflows, and Ansible playbooks. It respects multi-document YAML with --- separators.

The linter verifies that all anchors (&name) are defined before their aliases (*name) are used, checks for unused anchors, and detects circular references that could cause infinite loops.

Yes. All linting happens entirely in your browser using JavaScript. No YAML content is uploaded to any server. Your configuration files remain completely private.

While this tool focuses on detection and reporting, it provides clear suggestions for each issue. Many problems like indentation can be fixed automatically using a YAML formatter.

YAML Linter

Parsed Structure

Common YAML Linting Issues

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