HTML Minifier — Fast, Safe Online HTML Compression

Paste your HTML into the input area and adjust the toggle options to control which minification passes run. The tool performs conservative, deterministic transformations in this sequence:

1. Validation

• Input must be a string and under the recommended size (200 KB) to keep the browser responsive.
• The tool throws human-readable validation errors for empty or oversized inputs.

2. Comment removal (optional)

• Removes standard HTML comments while preserving conditional comments and common server-side or build directives to avoid breaking templates.

3. Inline block handling (optional)

• When enabled, the tool performs a lightweight safe-strip on content inside <style> and <script> tags: it removes block comments, strips simple line comments for JavaScript, and collapses internal whitespace. This is intentionally NOT a full JS/CSS minifier and is intended only for quick previews.

4. Boolean and empty attribute collapsing (configurable)

• Converts boolean attribute patterns like disabled="disabled" or selected="" into safe, shorter forms while preserving data-_ and aria-_ attributes unless explicitly allowed.

5. Whitespace collapsing (optional)

• Collapses consecutive whitespace and trims spaces between tags while protecting preformatted blocks (pre, textarea, code, script, style) to preserve semantics.

6. Result calculation

• The tool computes original and minified byte counts and the percentage savings using UTF-8 byte length, and surfaces non-fatal warnings if the minified output increases in size.

Design notes

• Safety-first defaults prevent accidental removal of template markers or accessibility attributes.
• The inline minifier is conservative; for production-grade JS/CSS minification prefer build tools like Terser, cssnano, or htmlnano.
• All processing is pure and runs in the browser, so no code leaves your machine.

When to use this tool

• Quick experiments and previews of minification impact.
• Verifying which rules change output size before adding minification to a build pipeline.
• Teaching or debugging how specific rules (comments, whitespace, boolean attributes) affect HTML size and render parity.