Text Diff Checker
Compare two versions of any text and see every change highlighted — lines added, removed, and unchanged. Perfect for content revisions, meta tag audits, and migration QA.
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Text Comparison Guide
Why line-level diffs beat eyeballing
A visual diff catches the tiny changes humans miss — a swapped word in a meta description, a dropped sentence in a blog draft, a single character flipped in a canonical URL. It's the fastest way to audit edits between two versions of anything text-based.
Content revision reviews
Paste your original draft on the left and the edited version on the right. Every added sentence, removed paragraph, and unchanged section is color-coded — no more scrolling to find what changed.
Meta tag audits
Exported your old meta tags before a migration? Paste them against what currently ships to confirm nothing was silently dropped. One line removed from a title tag can tank CTR overnight.
Migration QA
CMS migrations, template changes, and redirect mappings all produce side-effects. Diff the old output against the new one to catch unintended changes before they hit production.
Plagiarism spot-check
Compare your draft against a suspected source. While not a full plagiarism checker, the line-level view makes it obvious if two texts share identical sentences — a fast first-pass audit when you're briefing writers.
Whitespace-insensitive mode
Toggle 'ignore whitespace' to compare the meaning of text, not the formatting. Useful when comparing content from Word vs. Markdown vs. plain-text sources, which often differ only in spacing.
Case-insensitive mode
Toggle 'ignore case' when comparing URL slugs, email addresses, or anything where capitalization doesn't change meaning. Don't use it on body text — 'US' vs. 'us' genuinely matter in some contexts.
Pro Tips
The Swap button flips Original and Changed. Useful when you accidentally paste them the wrong way round — no need to re-paste.
The Similarity stat tells you what fraction of the longer text survived unchanged. Under 50% means major rewrite; 90%+ means a light edit.
Your text never leaves the browser. We do the diff in JavaScript right on your device — safe for confidential drafts, internal docs, and client content.
Frequently Asked Questions
- What size of text can this handle?
- Comfortably up to 1,500 lines per side. Beyond that the diff slows down because line-level LCS is O(n*m). For massive files, split them into sections and diff each separately.
- Does it detect moves?
- No — a moved line shows as one removal (from the original spot) plus one addition (at the new spot). True move detection requires a more expensive algorithm. For most editing workflows, add/remove is what you want anyway.
- How is this different from a word-level diff?
- Line-level diff is faster and easier to read for structured text like content, configs, or tag exports. Word-level diffs are better for prose where single-word changes matter a lot — we may add that as an option later.
- Can I diff code or HTML with this?
- Yes. It treats the input as plain lines of text, so source code, HTML, XML, CSS, and JSON all diff cleanly. For JSON specifically, format both sides first (with a JSON formatter) so indentation matches.