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name: broken-html description: "Use when auditing metadata, crawlability, structured data, or indexability related to Fix malformed HTML structure. Verify the rendered HTML and HTTP response rather than relying only on source files." metadata: category: seo priority: medium difficulty: intermediate estimatedTime: "10" source: frontendchecklist.io url: https://frontendchecklist.io/rules/seo/broken-html

Fix malformed HTML structure

Malformed HTML can cause rendering issues across browsers and may prevent search engine crawlers from accurately parsing and indexing your content.

Quick Reference

• Ensure all HTML tags are properly closed and nested according to specifications
• Remove stray tags or unescaped characters from the source code
• Verify the document structure follows a logical hierarchy with valid head and body sections

Check

Validate the HTML structure of the page to identify any unclosed tags, incorrect nesting, or structural errors.

Fix

Correct the malformed HTML by properly closing tags and ensuring all elements are nested according to the HTML5 specification.

Explain

Explain how significant HTML errors can impact search engine bot crawling and the accessibility of a website.

Code Review

Review metadata generation, rendered HTML, structured data, and response headers related to Fix malformed HTML structure. Flag exact routes or templates where search-facing output violates the rule, and describe how to verify the final page output.

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For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/rules/seo/broken-html