Compare text and find differences line by line
A fast, free diff checker for spotting changes between two pieces of text. Paste your before-and-after, see exactly what was added, removed, or unchanged — no signup, no upload, no waiting.
A diff (short for 'difference') is a structured comparison between two versions of text that highlights exactly what changed. Diffs are the foundation of version control systems like git — every commit, pull request, and code review revolves around them — but they're useful far beyond code.
Reach for a diff checker whenever you need to answer 'what's different between these two things?' faster than your eyes can. Comparing two contract drafts, two config files, two API responses, two translated documents, or two error logs all benefit from a tool that does the line-by-line work for you.
Paste your first text into the Text A panel and the second into Text B. Click Compare in the toolbar and the diff appears below: green lines with + were added in B, red lines with − were removed from A, and unchanged lines are dimmed. Use Swap A↔B to flip the direction, Copy diff to grab a patch-style snippet, and Clear to reset both panels.
Toggle between Unified view (one combined timeline of changes) and Split view (Text A on the left, Text B on the right) based on what's easier to scan.
Unified view stacks everything into a single column, with each line marked as added, removed, or unchanged. It's compact, great for short diffs, and matches the output of command-line tools like git diff. Split view places the two texts side-by-side so you can read them in parallel — useful when context matters, when changes are long, or when you're presenting a diff to someone who isn't used to reading patches.
Whitespace differences — extra spaces, tabs vs spaces, trailing newlines — are often noise. They make a diff look bigger than the actual change. Enable 'Ignore whitespace' to collapse all consecutive whitespace into single spaces before comparing, so you see only meaningful differences. This is especially helpful when comparing code formatted by different editors, or text pasted from sources that mangle indentation.
Yes. The diff algorithm runs entirely in your browser — the text you paste is never sent to a server, logged, or stored beyond your current tab. This makes Diff Checker safe for confidential documents, internal code, legal text, or anything else you wouldn't want to upload to a random web app.