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Format and validate YAML with syntax checks. Use for YAML editing; for JSON to YAML conversion use json-to-yaml, for TOML/YAML/JSON cross-conversion use toml-converter. Input: YAML ≤10MB. Returns formatted YAML or error. 100% client-side.
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Formats, validates, and minifies YAML content with configurable indentation, key sorting, and syntax validation. Detects YAML-to-JSON conversion for programmatic use, supports multi-document YAML streams, and provides detailed error messages for malformed YAML.
YAML is widely used for configuration files (Docker Compose, Kubernetes, CI/CD pipelines) but is notoriously sensitive to indentation errors. This tool helps developers validate, format, and convert YAML without hunting for invisible whitespace bugs.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
DevOps engineers managing Kubernetes or Docker Compose configs, CI/CD pipeline maintainers, Python developers using YAML for configuration, and anyone debugging YAML formatting issues.
Paste or upload your YAML content into the input area
Set indent size (2 or 4 spaces) — YAML does not support tabs for indentation
Toggle validation: the tool checks for common YAML errors (mixed indentation, trailing spaces, duplicate keys)
Select output format: Formatted YAML, Minified YAML, or JSON
Enable key sorting to alphabetically order top-level keys
Click "Format" and review the output; copy or download the result
Input: 'services: web: image: nginx' with 2-space indent. Output: 'services:\n web:\n image: nginx'Input: 'name: "hello"\ncount: 3' with sort keys. Output: 'count: 3\nname: "hello"'What YAML version does this support?
YAML 1.2 with most common 1.1 features.
Can I convert YAML to JSON?
Yes, the tool supports YAML-to-JSON conversion as an output option.
Does it handle multi-document YAML (--- separator)?
Yes, each document is processed independently.
What about anchors and aliases?
Anchors (&) and aliases (*) are preserved in formatted output but resolved in JSON conversion.
Authoritative specifications, standards, and in-depth reading for YAML Formatter/Validator.
View and navigate YAML with collapsible tree and validation. Use for read-only inspection; for editing/validation use yaml-formatter. Input: YAML ≤10MB. Returns tree view or error. 100% client-side.
Free online JSON formatter and validator with syntax highlighting and error line numbers. Use as default for beautify+validate+minify in one place; for two-file comparison use json-diff, for schema generation use json-schema-generator. Input: JSON ≤10MB. Returns formatted JSON or line-numbered error. 100% private.
Format and validate HTML with indentation and error reporting. Use as default HTML tool; for minifying production HTML use html-minifier, for converting HTML to Markdown use html-to-markdown. Input: HTML ≤10MB. Returns formatted HTML or validation errors. 100% client-side.
Format or minify CSS with indentation control. Use as default CSS tool handling both directions; css-minifier URL is a noindex alias. Input: CSS ≤10MB. Returns formatted or minified CSS. 100% client-side.
Minify JS for production or beautify minified JS for debugging. Use for JS only; for JSON use json-formatter, for CSS use css-formatter. Input: JS text ≤10MB. Returns minified or beautified JS or syntax error. 100% client-side.
Free online SQL formatter with indentation and keyword casing. Format queries privately in browser.
Format and validate XML with indentation and well-formedness checks. Use for XML; for JSON use json-formatter, for XML to JSON conversion use xml-to-json. Input: XML ≤10MB. Returns formatted XML or line-numbered error. 100% client-side.
Analyze text for word count, readability, and language stats. Paste and get instant insights.