Free HTML Formatter & Beautifier: Validate & Format HTML
Format messy HTML with proper indentation, remove HTML/CSS/JS/Jinja2 comments, strip empty lines, and validate syntax. Processing runs in your browser, so your code is not uploaded.
Syntax checker with line-numbered error reports: Detect unclosed tags, mismatched pairs, and invalid attributes before processing
Beautify HTML with consistent indentation: Apply consistent formatting to inline, minified, or poorly indented code
Remove HTML, CSS, JS, and Jinja2 comments: Strip all comment types in one pass, including server-side template comments
Remove empty lines to reduce file size: Eliminate unnecessary blank lines for cleaner, more compact output
Browser-based processing: Process HTML on the page without sending code to a server
Paste or type your HTML: Enter HTML code into the input panel. You can paste from your editor, CMS, or browser DevTools.
Validate syntax: Click "Check Syntax" to scan for unclosed tags, mismatched pairs, and other structural errors. Fix any issues by line number before processing.
Choose processing options: Enable "Format" for proper indentation, "Remove Comments" to strip HTML, CSS, JS, and Jinja2 comments, or "Remove Empty Lines" to reduce file size. Select one or more.
Process and export: Click "Process HTML" to generate the cleaned output. Download the result as an HTML file or copy it to your clipboard.
Practical Applications
Web developers — Clean up inherited legacy code and format third-party HTML templates into consistent, readable markup before release.
Content managers — Strip CMS-generated comments and empty lines from HTML before publishing, reducing page weight and keeping source code tidy.
Django and Flask developers — Remove Jinja2 template comments () alongside standard HTML, CSS, and JavaScript comments before deployment.
Students and learners — Paste unformatted HTML and use the Format option to visualize tag nesting and document structure, making it easier to understand how elements relate.
FAQ
Q. How do I use this free HTML formatter?
Paste your HTML code into the input panel, click "Check Syntax" to validate it, select your processing options (Format, Remove Comments, or Remove Empty Lines), then click "Process HTML." Download the result or copy it to your clipboard.
Q. What types of comments does the HTML formatter remove?
Four types: standard HTML comments (<!-- -->), CSS block comments (/* */) within <style> tags, JavaScript single-line (//) and multi-line (/* */) comments within <script> tags, and Jinja2 template comments ({# #}). All are stripped in a single pass.
Q. Will formatting HTML break my website's layout?
The formatter changes whitespace, indentation, and line breaks without reordering HTML tags, attributes, or text content. Review the output before publishing if your page depends on exact whitespace in inline content.
Q. Can I process HTML with embedded CSS and JavaScript?
Yes. The tool handles full HTML documents and formats CSS within <style> blocks and JavaScript within <script> blocks alongside the HTML markup. Comments in all three languages are removed when the option is enabled.
Q. What happens if my HTML contains syntax errors?
The built-in syntax checker detects unclosed tags, mismatched pairs, and invalid attributes, then lists each error with its line number and a description. Fix the errors in your source code and re-run validation — processing is blocked until your HTML passes the check.
About This Free HTML Formatter & Beautifier
This free HTML formatter beautifies messy, minified, or inconsistently indented HTML. Paste any HTML — including documents with embedded <style> and <script> blocks — and choose whether to format markup with consistent indentation, remove comments, strip empty lines, or apply all three options. The built-in syntax checker detects unclosed tags, mismatched pairs, and invalid attributes before processing begins.
All processing runs in your browser using the native HTML parser — your code is never uploaded. The formatter handles HTML with embedded CSS and JavaScript, and removes Jinja2 template comments ({# #}) alongside standard HTML, CSS, and JS comments, which is useful for Django and Flask developers working with template files.
Use it to clean up inherited legacy code, prepare HTML for publication, learn HTML document structure, or maintain Jinja2-based template projects.
HTML Comment Types This Tool Removes
HTML:<!-- comment -->
CSS:/* comment */ (within <style> tags)
JavaScript:// single-line and /* multi-line */ (within <script> tags)
Jinja2:{# comment #} template tags
Built-in Syntax Checker
The built-in syntax checker uses your browser's native HTML parser to detect unclosed tags, mismatched pairs, and invalid attributes. Each error is listed with its line number and a description. Processing is blocked until your HTML passes validation.
When to Use This HTML Formatter
Clean up inherited or legacy code: Web developers often receive HTML files with inconsistent indentation, leftover comments, and extra empty lines. Paste the file, choose the options you need, and produce consistently formatted, readable markup.
Prepare HTML for production deployment: Before pushing HTML to a live server, strip developer comments and empty lines to reduce file size and avoid exposing internal notes in page source. Skip formatting to preserve minification if file size is the priority.
Format HTML from CMS or WYSIWYG editors: Content management systems often generate HTML with messy markup. Paste the source code, format it for readability, and remove auto-generated comments before making manual edits.
Maintain Django and Flask templates: Remove Jinja2 template comments ({# #}) alongside standard HTML, CSS, and JS comments. Use it to clean up .html template files before committing them to version control, so internal logic notes are not left in production templates.
Debug HTML structure and nesting issues: Students and beginners can paste their HTML and click "Check Syntax" to see which tags are unclosed or mismatched, listed by line number. Formatting the corrected code with proper indentation makes the document structure easier to scan.
Process copied snippets from browser DevTools: When inspecting elements in Chrome or Firefox DevTools, the copied HTML is often compressed onto a single line. Paste it here, click "Process HTML" with formatting enabled, and get readable, properly indented code.
Tips for Getting the Most Out of This HTML Formatter
Always run "Check Syntax" first: Even if your code looks fine, the browser's native parser may detect issues you missed, such as unclosed <p> tags, missing closing </div> tags, or mismatched nesting. Fix errors before formatting the checked code.
Use "Remove Comments" before deployment: Developer comments often contain internal notes, to-do items, or debugging information that should not appear in production HTML. Enable this option before deploying to keep page source cleaner.
Skip formatting when file size matters: If you are optimizing for performance and the HTML is already minified, enable only "Remove Comments" and "Remove Empty Lines." This reduces file size without adding indentation whitespace.
Process Jinja2 templates with care: Jinja2 tags like {% %} and {{ }} may trigger false positives in the syntax checker because they are not standard HTML. Review any reported errors carefully. The line numbers are still useful for locating issues, but not every flagged error is a real problem in a template context.
Copy from browser DevTools for quick formatting: When inspecting an element in Chrome or Firefox, right-click the element and choose "Copy > Copy outerHTML." Paste the result here and format it to read compressed or dynamically generated markup.
Processing stays local: All HTML processing happens in your browser. Your code is not uploaded to a server.
ToolkitBook