Text Compare (Diff Checker)

Compare two, three or more texts side by side — added, removed and changed lines highlighted, like a visual merge tool.

Fill in at least two texts, then press Compare.

🔒 Runs entirely in your browser — nothing you type is uploaded or stored on a server.

The Text Compare tool shows you exactly what changed between two versions of a text, laid out side by side like a visual merge tool. Paste an original and a revision and every line is aligned: unchanged lines sit level, added lines light up green, removed lines red, and edited lines show the old and new text next to each other in amber. It is built for spotting the real differences between drafts, configs, logs or code fast.

Also on Txtset: find and replace words in multiple lines.

Comparing documents by eye is slow and unreliable — a single changed word in a contract, an edited paragraph in an essay, or one modified line in a configuration file is easy to miss. A diff checker does the comparison mechanically, the same way programmers review code changes, so nothing slips past. You can also compare more than two inputs: add a third, fourth or fifth text with “+ Add another text” and choose which text acts as the base.

The comparison is a proper line-level diff (a longest-common-subsequence alignment). Options let you ignore extra spaces and letter case so formatting noise doesn't drown out real edits. Both texts are compared entirely in your browser — nothing is uploaded, so it's safe for contracts, code and confidential drafts.

How to use

  1. Paste your first version into text A and the next into text B.
  2. Add more texts with “+ Add another text” to compare three or more at once (up to six).
  3. Choose which text to compare the others against with the “Compare against” selector.
  4. Toggle “Ignore extra spaces” or “Ignore case” if those differences don't matter to you.
  5. Press Compare — removed lines show in red, added lines in green, edited lines in amber.

Examples

Reviewing an edit
Paste your draft and the edited version a colleague sent back — every line they touched is highlighted, so you can accept or question each change.
Checking AI rewrites
Compare your original paragraph with a ChatGPT rewrite to see precisely which sentences were altered.
Multiple config files
Compare staging, production and a backup against one base to spot which settings drift between environments.
Verifying two copies
Paste both copies of a document; if the result says “identical”, you know no sneaky changes were made.

Frequently asked questions

How does the comparison work?
It uses the longest-common-subsequence alignment from standard diff tools: it finds the largest set of lines the texts share, then marks everything else as added, removed or edited.
Does it compare word by word or line by line?
Line by line. Each line of the original is matched against the changed text, which keeps the output easy to scan. Changed lines are highlighted side by side.
Can I compare more than two texts?
Yes. Click “+ Add another text” to compare up to six texts against one base at the same time.
What does “ignore extra spaces” do?
Lines that differ only in spacing — double spaces, tabs, or leading and trailing blanks — are treated as identical, so formatting noise doesn't drown out real edits.
Is there a size limit?
Each side can hold up to 4,000 lines, which covers most documents. For very long texts, compare them section by section.
Can I compare code with it?
Yes — it's line-based, exactly like a code diff. Developers use it for quick comparisons without opening an editor or committing to git.
Is my text uploaded?
No. All comparison runs entirely in your browser with JavaScript. Nothing is sent to a server, making it safe for private and confidential documents.

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