HTML Validator — developer utilities, encoders and data format tools
The HTML Validator checks your markup for the most common structural problems before you deploy it. It flags a missing DOCTYPE declaration, missing html, head, and title tags, a missing charset meta tag, and the use of !important in inline styles. It also counts open and close tags to warn you when
Category: Developer Tools
About this tool
What Is HTML Validator? HTML Validator is a browser-based tool for Validate HTML structure and find syntax errors. This guide explains the result, the calculation or processing method, and correct usage. Calculation or Processing Method The tool applies the operation described in its interface: Validate HTML structure and find syntax errors. Processing method: The tool produces the result using a processing method appropriate to the input data type. How to Use It Open the tool and choose the required unit, mode, or options. Enter values or paste text into the input fields. Review the result, copy it, or continue with a related tool. Important Notes Use consistent units and verify values before calculating. Incomplete or invalid input can produce an incomplete result. Related Tools Tools that support the same workflow: JSON Formatter — Format, validate, and minify JSON with syntax highlighting. Base64 Encoder/Decoder — Encode and decode text or files in Base64. Hash Generator — Generate MD5, SHA-1, SHA-256 hashes for text. Frequently Asked Questions How does HTML Validator work? The tool processes input according to its purpose: Validate HTML structure and find syntax errors. Are HTML Validator results accurate? Results are deterministic when input and units are correct.