SuperHTML – HTML validator, formatter and language server

SuperHTML is an HTML validation and formatting tool with an integrated Language Server Protocol implementation.

Its validator aims to understand HTML according to the WHATWG living specification rather than merely checking whether markup is syntactically well formed. This lets it detect problems involving element nesting and attribute values as well as basic parsing errors. The same executable provides checking, formatting and language-server functionality, making it suitable for interactive editor use and automated project checks. SuperHTML concentrates on HTML5 and deliberately makes some stricter choices where permissive browser behaviour could conceal likely authoring mistakes. It also includes a separate templating-language library, although full validation of documents containing popular third-party template syntaxes remains more limited than validation of ordinary HTML.

This is free and open source software.

Key Features

• Validates HTML syntax, element relationships and permitted attribute values.
• Provides diagnostics based on detailed knowledge of the HTML specification.
• Includes an autoformatter with whitespace-sensitive control over vertical and horizontal element layout.
• Can check formatting in continuous integration without rewriting source files.
• Offers a built-in language server for editors supporting the Language Server Protocol.
• Supports editor integration with VS Code, Neovim, Helix, Vim, Zed and other LSP-capable environments.
• Provides a syntax-only mode for documents containing templating constructs that cannot yet undergo full validation.
• Can format documents or selected text through standard editor formatting mechanisms.
• Flags unsupported document types rather than silently changing its HTML interpretation.
• Includes command-line subcommands for checking documents, formatting files and starting the language server.
• Provides a templating-language library alongside its HTML parser and developer tooling.

Website: github.com/kristoff-it/superhtml
Support:
Developer: Loris Cro
License: MIT License

SuperHTML is written in Zig. Learn Zig with our recommended free tutorials.

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