Validate your HTML code instantly to ensure it meets modern web standards and is free of syntax errors. Get detailed feedback on unclosed tags, attribute nesting, and document structure to improve your site SEO and accessibility.
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Tip
Fix the very first error in the list first; one unclosed tag often triggers many 'ghost' errors further down the page.
Did You Know?
Valid HTML is a prerequisite for high-quality SEO, as it ensures search engine bots can parse your site's hierarchy correctly.
<div> or <span> can break the entire layout logic of your pagealt for images<center> or <font> that are no longer supported in modern HTML5 standards<div>) inside inline elements (like <a>) incorrectlyBest Practice
Always include a lang attribute in your opening html tag to help screen readers and search engines identify your content language.
<header>, <footer>, and <main> over generic <div> tags for better structure<img> tags have descriptive alt attributes to pass accessibility validationQ: Does this validator support HTML5? A: Yes, the tool is fully updated to support the latest HTML5 specifications and elements.
Q: Can it detect broken external links? A: No, this tool focuses on syntax and structural validation of the markup itself rather than checking external URL status.
Q: Why does my page look fine even with validation errors? A: Modern browsers are designed to be forgiving and will attempt to fix bad HTML on the fly, but this can lead to performance hits and inconsistent behavior.
Q: Does this tool validate CSS inside style tags? A: This tool primarily checks HTML structure. For dedicated CSS validation, we recommend using our CSS Validator tool.
Tip
Use the HTML Formatter after fixing your errors to ensure your code is both valid and beautifully organized.