How does the text diff checker work?

Paste your original text on the left and the changed text on the right. The tool compares them line by line using a longest-common-subsequence algorithm and highlights every added line in green and every removed line in red, with a summary count.

Can it ignore case and spacing differences?

Yes. Toggle 'ignore case' to treat 'Hello' and 'hello' as identical, and 'ignore leading/trailing spaces' so indentation or trailing whitespace changes don't create false differences.

Is my text kept private?

Completely. The comparison runs entirely in your browser — neither version of your text is ever uploaded, so contracts, code and confidential drafts stay on your device.

What is the difference between this and a word-level diff?

This tool compares line by line, which is ideal for documents, code and lists. It marks whole lines as added or removed, making structural changes easy to spot at a glance.

Can I compare code with it?

Yes — it works well for source code, config files and logs. Because it compares lines, it clearly shows which lines were inserted, deleted or modified between two versions.

Text Diff Checker

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Text Diff Checker — See Exactly What Changed, Line by Line

When two versions of a document, contract, or code file look nearly identical, spotting the differences by eye is slow and error-prone. This free diff checker compares two blocks of text and highlights every change: added lines in green, removed lines in red, with a running count of additions, deletions and unchanged lines. Everything runs privately in your browser — no upload, no signup, no limits.

How the Comparison Works

The tool uses a longest-common-subsequence (LCS) algorithm — the same core technique behind git diffs and version-control systems. It finds the largest set of lines the two texts share in order, then marks everything else as added or removed. The result is a clean, aligned view where matching content stays put and only the real changes stand out.

Ignore Options That Prevent False Positives

Ignore case: treats "Section" and "section" as the same, so capitalization edits don't clutter the results.
Ignore leading/trailing spaces: stops indentation tweaks or stray trailing spaces from showing up as changes — invaluable when comparing code or reformatted text.

Who Uses a Diff Checker

User	Typical task
Writers & editors	Compare draft revisions to see an editor's exact changes
Developers	Diff two versions of a config file, script or snippet outside an IDE
Legal & contracts	Spot every altered clause between two contract versions
Students & researchers	Check what changed between paper drafts or citations

Why Private, In-Browser Comparison Matters

Many online diff tools send both texts to a server. For contracts, unpublished writing, or proprietary code, that's a real privacy risk. This tool never transmits your text — the entire comparison happens locally, so even the most sensitive documents stay on your machine. Paste freely, compare instantly, and copy the result wherever you need it.