Paste or type your code below to instantly format, beautify, compact, or structurally validate it using our free online YAML Formatter. This browser-based developer tool helps you structure complex YAML (YAML Ain’t Markup Language) documents with clean, consistent 2-space indentation without uploading data to external servers.
Your YAML is processed locally in your browser and is not uploaded to our server.
How to Use Our YAML Formatter Tool
- Paste or type your YAML into the input panel.
- Click Format / Beautify for consistent, readable indentation, Compact YAML to strip comments and blank lines, or Validate to check for common structural mistakes.
- Use Copy Output or Download to take the result with you.
What This Tool Actually Supports
This is a practical formatter and validator for common real-world YAML — not a full YAML 1.2 specification implementation. It handles mappings and sequences (including nested), quoted and plain scalars, literal (|) and folded (>) block scalars, comments, document markers (--- / ...), flow collections ({} / []), and anchors/aliases/tags — all preserved as written, never resolved or interpreted. It does not implement the complete YAML grammar, and it never executes, evaluates, or deserializes anything in your document, no matter what tag or content it contains.
Why “Compact”, Not “Minify”?
Unlike JSON, CSS, or JavaScript, YAML’s indentation and line breaks are part of its actual syntax — removing them the way a JSON minifier removes whitespace would produce invalid YAML. Compact YAML instead removes full-line comments and blank lines (except inside block scalars, where blank lines can be part of the literal text) while keeping clean, valid, consistent indentation.
What Validate Actually Checks
Validate is a structural check, not a full YAML grammar validator. It detects tab characters used for indentation (invalid in YAML), unclosed quoted strings, indentation that doesn’t line up with any enclosing level, and an unclosed flow collection bracket — reporting the exact line and column. It does not check key uniqueness, verify tag syntax against a schema, or resolve anchors/aliases.
FAQ
Is my YAML file uploaded to any external server?
No, absolutely not. Formatting, compacting, and validating all happen locally inside your web browser using JavaScript. Therefore, your sensitive configuration files remain completely private and secure.
Will using the YAML Formatter alter my underlying data?
No. The YAML Formatter normalizes indentation to a clean 2-space layout while leaving key-value data, comments, and scalar content unchanged. Furthermore, text inside literal or folded block scalars preserves its original formatting.
Is there a file size limit for formatting YAML online?
There is no artificial file size limit imposed by our server. However, processing extremely large files depends on your browser’s local memory performance because execution runs client-side.
Do I need an account?
No. The tool is free to use and doesn’t require sign-up.