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Home / HTML Tools / HTML Syntax Checker
HTML Tools

HTML Syntax Checker

Paste HTML to compare focused source diagnostics with the browser-parsed DOM without sending markup to a server.

0Focused issues
0Parsed elements
0Source lines
0Unique IDs
HTML source diagnosticsThis is not the full WHATWG parse-error stream; browsers can recover from malformed markup in ways a simple source stack cannot represent.
HTML structure counting workflow

When you need a page-wide inventory before deeper diagnostics, use the HTML Tag Counter to compare parsed tag frequency, percentage distribution, nesting depth and approximate source-token differences.

Browser-local does not mean standards-complete

HTML parsing is error tolerant. Source diagnostics, sandboxed previews, and transformations do not replace full conformance, security, or production-browser testing.

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