About This Tool
Documentation
What does this tool do?
An AST-based HTML formatter and validator. Beautifies nested DOM structures with customizable tab widths (2/4 spaces, tabs), configures attribute wrapping and bracket positioning, validates HTML5 tag hierarchy, and detects unclosed tags or syntax malformations with line numbers.
When should you use it?
Use this tool to clean up messy HTML source code, format scraped web markup for inspection, verify HTML5 semantic validity, and ensure consistent indentation across team projects.
Key Capabilities & Features
Highlights
W3C HTML5 specification syntax validation and semantic markup diagnostics
Beautify and format messy HTML codebases with consistent nesting and indentation
Detect unclosed tags, duplicate attributes, mismatched tags, and invalid element nesting
Customizable formatting rules (indent size, wrap line length, void tag styling)
Live visual preview of formatted HTML with one-click copy and download