Text Diff Checker
Highlight every addition and deletion between two text blocks — instantly
Diff will appear here when both panels have text
Paste your original text on the left and the revised version on the right — additions appear in green and deletions in red, character by character. Works for plain text, code, JSON, YAML, Markdown, or any text format. Everything runs in your browser.
How to Compare Two Texts
Paste both versions and see a highlighted diff in seconds — no signup needed.
Paste original and revised text
Enter or paste your original text in the left panel and the revised version in the right panel. Supports plain text, code, JSON, YAML, Markdown, or any text format.
Instant diff highlight
The diff updates live as you type. Additions are highlighted in green and deletions in red, with line numbers shown for easy navigation.
Copy or share the diff
Copy the highlighted diff report, or share a URL with the comparison pre-loaded so colleagues can review the same changes.
Features
Runs entirely in your browser — your text never leaves your device
Line-by-line diff with additions highlighted in green and deletions in red
Dual line numbers for original and revised versions — easy to navigate
Works with plain text, code, JSON, YAML, Markdown, SQL, or any text format
Live diff updates as you type — no submit button needed
Addition and deletion counters shown in the output header
Compact table layout makes reviewing large diffs fast and clear
Click Sample to instantly see a real code diff example
Free, no sign-up, no character limits
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Frequently Asked Questions
Does my text get sent to a server?
No. All comparison happens inside your browser using a JavaScript LCS (Longest Common Subsequence) algorithm. Your text never leaves your device.
What diffing algorithm does this tool use?
The tool uses a Longest Common Subsequence (LCS) algorithm — the same approach used by Unix diff and Git. It computes the minimal set of additions and deletions needed to transform the original text into the revised version, line by line.
Can I diff code files, JSON, or YAML?
Yes — anything text-based works. Paste JavaScript, Python, JSON, YAML, SQL, Markdown, HTML, or any other text format. The diff is purely textual.
Is there a character or line limit?
No hard limit. For very large texts the diff may take a moment, but there is no artificial cap.
Can I compare two versions of a document?
Yes. Paste the original version on the left and the revised version on the right. The diff immediately shows what was added, removed, and unchanged.
How do I share a diff with a colleague?
Currently the diff is local only — there is no shareable URL. Copy the output or take a screenshot to share.