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HTML Diff Viewer — Compare Before & After HTML

Paste two versions of HTML and see exactly what changed. Side-by-side diff view helps you verify your HTML cleanup results.

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HTML Diff Viewer

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How It Works

1.Paste Original HTML

Paste the original or 'before' version of your HTML into the left panel.

2.Paste Changed HTML

Paste the cleaned or 'after' version of your HTML into the right panel.

3.Review the Diff

See exactly what changed — green for additions, red for removals. Copy or download the diff result.

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Why Diff Viewers Help

When cleaning HTML from Google Docs, it's easy to accidentally remove something important. A diff viewer lets you verify exactly what was removed so nothing essential gets lost.

  • Verify cleanup results before publishing
  • Catch accidental removals of important markup
  • Learn which cleanup options affect your content
  • Share before/after comparisons with your team
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All Tools

SEO Slug Generator

AI-powered title to URL slug

CJK Auto-Spacing

Space CJK & Latin text

Content Stats

Word count, reading time & more

A11y Checker

Check HTML accessibility issues

OG Image Generator

Create social share images

Markdown Converter

HTML to Markdown and back

TOC Generator

Table of contents from headings

JSON-LD Builder

Schema markup for SEO

Or start with the main HTML cleanup tool

Open Publish Helper
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Frequently Asked Questions

Is my HTML sent to a server?

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No. Everything runs in your browser. Your HTML never leaves your machine.

Can I compare very long HTML?

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Yes. The diff handles documents of any length, but very large documents may take a moment to process.

Does this work with any HTML?

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Yes. Paste any HTML — from Google Docs, WordPress, or hand-written markup.

Is this tool free?

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Yes, completely free with no signup required.

Changelog

v3.0.02026-05-03
  • NewHTML Diff Viewer — compare before and after HTML with a visual diff (green/red)
  • NewContent Stats Calculator — word count, reading time, heading, image, and link counts
  • NewHTML Accessibility Checker — detect missing alt text, empty headings, skipped levels, and more
  • NewOG Image Generator — create 1200×630 social share images from your blog post title
  • NewMarkdown ↔ HTML Converter — bidirectional conversion between Markdown and HTML
  • NewTable of Contents Generator — auto-generate nested TOC from heading tags in HTML or Markdown
  • NewJSON-LD Structured Data Builder — generate Article, BlogPosting, and FAQPage schema markup
  • NewAuto-clean on paste — optional toggle that auto-triggers cleanup when content is pasted
  • NewTable cleanup options — strip cell widths and remove empty table cells
  • NewAuto-save draft — content is saved to localStorage and restored on accidental refresh
  • NewAll new tools linked from the main page TOOLS & GUIDES section and related pages
v2.4.12026-04-27
  • NewParagraph option added to heading dropdown — convert headings back to normal text
  • FixH1–H6 heading prefixes now convert correctly even when pasted with leading line breaks
  • FixFixed page crash on load — cookie consent now renders reliably
  • ImprovedDependency updates for better performance and stability
v2.4.02026-04-17
  • NewClear button — quickly wipe all editor content and reset the HTML panel from the left panel header
  • FixEmpty <p></p> placeholder no longer appears in the HTML panel after clearing the editor
  • NewImage insert via URL — paste any image URL into the editor with a new toolbar popover
v2.3.22026-04-14
  • FixHeading conversion rewritten with DOM parsing — now works with any wrapper tag, split headings (H1 + body in same <p>), and safely preserves <li> inside lists
  • FixEmpty heading tags left behind by Google Docs are now automatically removed
v2.3.12026-03-25
  • FixHeading conversion now handles spaces before the colon (e.g. "H2 : Title")
  • FixRight-to-left content (Arabic, Hebrew) no longer inverts embedded English text in the editor
  • FixSpacer paragraphs (&nbsp;) are now preserved in the HTML output instead of being stripped
v2.3.02026-03-20
  • NewCJK auto-spacing — automatically insert spaces between Chinese/Japanese/Korean characters and English letters or numbers (powered by pangu.js)
  • NewStandalone CJK Auto-Spacing tool page with before/after examples, FAQ, and SEO-optimized bilingual content
  • NewChinese UI text auto-spacing — zh-TW interface text now has proper CJK–Latin spacing
  • FixMobile toolbar no longer floats and follows scrolling — stays pinned at the bottom of the editor
  • FixMobile toolbar buttons now scroll horizontally instead of overflowing
  • FixFind & Replace inputs no longer break out of the container on narrow screens
v2.2.12026-03-20
  • FixHeading conversion now uses the text prefix (e.g. H3:) to set the heading level, even when the content is already inside a different heading tag
v2.2.02026-03-18
  • NewAI-Powered Title to SEO Slug — Convert blog titles in any language to SEO-friendly English slugs in under 10 seconds
  • NewSlug generator toggle on the main page — generate slugs right after editing, above the fold
  • NewTable support — pasted tables from Google Docs now render correctly
  • NewRemove <br> after headings cleanup option (on by default)
  • NewPartial text selection copy in the HTML code view
  • NewSticky Clean HTML button at the bottom of the page
  • ImprovedHeading conversion now strips prefixes from existing heading tags and supports Chinese full-width colon (：)
  • ImprovedShared footer across all pages
v2.1.22026-03-17
  • FixBug fixes and improvements
v2.1.12026-03-16
  • FixBug fixes and improvements
v2.1.02026-03-16
  • NewFormatted/Raw toggle for the HTML code view
  • ImprovedCopying from the code panel now always gives clean, unformatted HTML
v2.0.02026-03-16
  • NewWelcome to Publish Helper — free online tools for content editors
  • ImprovedImproved search engine visibility
v1.1.02026-03-16
  • ImprovedClipboard copy — clean HTML output matches the code view
v1.0.02026-03-16
  • NewRich text editor with Google Docs paste support
  • NewHTML cleanup: strip styles, classes, empty tags, and Google Docs artifacts
  • NewHeading conversion from text prefixes to proper HTML tags
  • NewFind & replace with regex support and saveable presets
  • NewSyntax-highlighted HTML preview with one-click copy
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