Online tag checker

Validate HTML and XML tags for proper nesting, missing tags, and syntax errors with instant feedback.

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9,148+

Total Calculations Run

< 15ms

Browser Execution Speed

100%

Client-Side Privacy

4.9 / 5.0

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About This Tool

The Online Tag Checker is a comprehensive tool for developers and content creators to validate HTML and XML code. It analyzes your markup to identify unclosed tags, improper nesting, missing attributes, and other common issues. Simply paste your code or upload a file to get detailed error reports with line numbers and suggestions for fixes. The tool supports both HTML5 and XML standards, making it perfect for web development, document validation, and quality assurance workflows.

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How to Use

Paste your HTML or XML code into the text area OR click the upload area to select a file.
Click the 'Check Tags' button to analyze your code.
View the results showing errors, warnings, and statistics about your tags.
Use the 'Clear' button to reset the form and start over.

Frequently Asked Questions

Find Quick Answers

What types of tags does this tool check?

The tool checks HTML tags (including HTML5) and XML tags for proper syntax, nesting, and closure. It validates both opening and closing tags, self-closing tags, and attribute syntax.

Can I upload files for validation?

Yes, you can upload .html, .htm, .xml, and .txt files directly. The entire dropzone area is clickable for easy file selection.

Does this tool require an internet connection?

All processing happens client-side in your browser, so no data is sent to external servers. This ensures privacy and fast performance.

What common errors does the tool detect?

The tool detects unclosed tags, mismatched opening/closing tags, improper nesting, missing required attributes, duplicate IDs, and invalid characters in tag names.

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