Beautify or minify HTML markup instantly, with customizable indentation, attribute formatting, and file-size compression stats.
Beautifying reprints your markup with consistent indentation, attribute wrapping, and readable nesting. Minifying collapses safe whitespace and optional comments so transfer size drops. Script, style, pre, and textarea contents are left intact so JavaScript, CSS, and significant whitespace are not rewritten.
A Valid status means the tokenizer accepted the document and tags balanced. That is not a WHATWG/W3C conformance check. Browsers recover from many HTML errors, so this workspace reports unclosed tags, mismatched closers, malformed comments, unclosed quotes, and duplicate IDs as diagnostics rather than claiming a full standards validator is running.
Safe Preview renders a visual snapshot inside a sandboxed iframe with scripts, same-origin access, and inline event handlers blocked. It is a layout check, not a live page.
Paste, upload, format, minify, copy, and download never leave this page. Companion tools include the <a href="/json-formatter" class="text-brandBlue-400 hover:underline font-semibold">JSON Formatter</a>, <a href="/xml-formatter" class="text-brandBlue-400 hover:underline font-semibold">XML Formatter</a>, <a href="/css-minifier" class="text-brandBlue-400 hover:underline font-semibold">CSS Formatter</a>, and <a href="/javascript-minifier" class="text-brandBlue-400 hover:underline font-semibold">JavaScript Minifier</a>.
Quick answers about how this tool works.
Plain-language explainers that sit next to this tool.
Input tokens, output tokens, cached tokens and cache writes — what each one costs on GPT-6 Astra, what actually counts toward your input bill, and three worked examples showing where the money really goes.
Minification, uglification, and bundling get lumped together as "build steps," but each does something distinct. Here is exactly what each one changes in your code, with a before/after size example.
Auto-increment IDs leak your record count. Random UUIDs wreck index locality at scale. Here is a framework for choosing a primary key strategy based on how distributed your system actually is.
The same API endpoint can return JSON, XML, or HTML depending on one request header. Here is how Accept and Content-Type headers negotiate response format, and what a 406 actually means.
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