Private & local
All comparison happens in your browser. Nothing is uploaded, logged, or stored — your text never leaves your device.
Text Diff
Compare two texts line by line online — free, fast, private. See differences highlighted instantly. All processing happens in your browser, no data uploaded.
Text Diff
Compare two texts line by line. Paste your original and modified text — diffs update as you type.
How to use the Text Diff tool
Three simple steps — no signup, no upload, no waiting.
- Paste your original text into the left textarea. This is your baseline — the text you want to compare from.
- Paste the modified text into the right textarea. This is the updated version you want to compare against.
- Differences appear automatically as you type. Added lines show in green with a + prefix, removed lines in red with a - prefix. Unchanged context lines appear in gray for reference.
Features
A local text diff tool built for quick comparisons.
Instant compare
No waiting for server responses. Line-by-line diff runs instantly in your browser — see results with color-coded additions and deletions right away.
Easy to share
Copy the unified diff output with a single click. Paste it into code reviews, documentation, or share with your team — formatted and ready to go.
Frequently asked questions
Common questions about text diff and how our tool works.
What is a text diff?
A text diff compares two pieces of text and shows what changed between them. Added lines are marked with a + (green), removed lines with a - (red), and unchanged lines appear in gray. It's the same concept behind tools like git diff — useful for reviewing changes in code, documents, or any text.
How does the diff work?
Our tool splits both texts into lines, then uses a line-by-line comparison algorithm to find the longest common subsequence. Added lines are lines present in the modified text but not the original; removed lines are lines in the original but not the modified. Unchanged lines around changes are shown for context.
Does my text get uploaded anywhere?
No. All comparison runs locally in your browser using JavaScript. Your text never leaves your device — there is no server step, no API call, and nothing to log. You can verify this by disconnecting your internet after the page loads — the tool works fully offline.
Can I compare code with this tool?
Yes. The text diff tool works great for comparing code snippets, configuration files, or any plain text content. It handles indentation, special characters, and long lines. For syntax highlighting, you can copy the diff output into your editor. The tool processes text line by line, so it works with any programming language or plain text format.
What is a unified diff?
A unified diff shows all changes in a single column rather than side by side. Each changed line is prefixed with + (addition) or - (removal), with a few unchanged context lines around each change. This format originated with Unix diff -u and is the standard format for code review, patches, and version control systems like Git.