Prettify and validate HTML code. This tool is designed to provide a seamless experience for developers by handling complex operations directly in the browser.
HTML (HyperText Markup Language) is the foundation of the web. However, as web applications grow in complexity, HTML code can quickly become a tangled mess of nested tags and attributes. Our HTML Formatter/Validator is a professional tool designed to bring order to your markup. It parses your HTML input and transforms it into a clean, hierarchical structure with consistent indentation and line breaks. This makes it much easier to understand the relationship between elements and to identify structural issues. The built-in validator is particularly useful for catching common errors like unclosed tags, which can cause significant rendering issues in browsers. By using this tool, you can ensure your HTML is clean, readable, and follows the latest web standards.
Paste your raw or minified HTML code into the editor. Click "Format" to apply consistent indentation and line breaks. The tool will validate your HTML against standard rules, highlighting any unclosed tags or invalid attributes.
For web developers, clean markup is essential for maintainability and debugging. Our HTML Formatter/Validator provides instant clarity, allowing you to quickly navigate through complex layouts and identify issues. It's an invaluable tool for anyone working with modern web frameworks, where HTML is often generated dynamically. The real-time validation pinpointing exact line numbers where a tag is missing or an attribute is invalid saves significant time and frustration. Furthermore, because this tool runs entirely in your browser, your proprietary markup and sensitive data never leave your machine, providing a secure environment for managing your most critical web assets.
Unclosed Tags: An opening tag does not have a corresponding closing tag.
Fix: Ensure every <div> has a matching </div> and that they are properly nested.
Invalid Attributes: Attributes are missing quotes or have illegal characters.
Fix: Wrap all attribute values in double quotes (e.g., class="container").
Missing DOCTYPE: HTML documents should start with a DOCTYPE declaration.
Fix: Add <!DOCTYPE html> to the top of your document.
What is URL Encoding and Decoding Explained: Complete Guide 2026
What is URL Encoding and Decoding Explained: Complete Guide 2026. Learn how URL encoding works, encodeURI vs encodeURIComponent, when to encode, common mistakes, and real-world best practices.
Best Free Online Developer Tools You Should Use in 2026: The Ultimate List
Discover the best free online developer tools in 2026. Explore LearnHubly's privacy-first suite including JSON Formatter, Base64 Encoder, JWT Decoder, UUID Generator, SQL Formatter, and 60+ more tools. Boost productivity with zero-install, client-side utilities.
Online vs Offline Developer Tools in 2026 – Which is Better?
Online vs Offline Developer Tools in 2026 – Which is better? Honest comparison of web-based vs desktop tools focusing on privacy, speed, convenience, and performance. Discover why local-first online tools like LearnHubly are becoming the preferred choice for modern developers.
Does it support HTML5?
Yes, the formatter is fully compatible with the latest HTML5 specification.
Can it handle large HTML files?
It is optimized for performance and can handle files up to several megabytes.
Is it safe for sensitive data?
Yes, the tool runs entirely client-side, so your data is never sent to a server.
Recent Activity
No recent activity