How it works
When you have two versions of a text, such as a config file before and after a change, two API responses or two versions of a SQL query, spotting the differences by eye is slow and error-prone. Paste the original on the left and the modified text on the right, and the tool shows a unified view with added lines in green, removed lines in red and the line numbers on each side.
At the top you see the count of added and removed lines. Only changes hides lines that did not change so you can focus on what matters, and Ignore trailing whitespace keeps an editor that trims spaces from filling the result with false changes. Windows line endings (CRLF) are normalized automatically.
The swap button flips original and modified, handy when you pasted them the wrong way around. The comparison uses the longest common subsequence algorithm, the same foundation as diff and git diff, and updates as you type.
Since everything runs in your browser, you can compare files with credentials, internal logs or customer data without uploading them anywhere.
Examples
Changes in a config file
Original: Modified:
host: localhost host: localhost
port: 8080 port: 9090
debug: true debug: false
log: info 1 1 host: localhost
2 + port: 9090
3 + debug: false
4 + log: info
2 - port: 8080
3 - debug: true
+3 −2Ignore trailing whitespace
Original: "a = 1 " / "b = 2" Modified: "a = 1" / "b = 2"
No differences
Frequently asked questions
Which algorithm does it use?
It computes the longest common subsequence of lines, the same idea behind diff and git diff. Equal lines are kept and the rest show up as added or removed.
Is there a size limit?
You can compare files with thousands of lines. If the two texts differ in too many lines to compute without freezing the tab, the tool tells you instead of hanging.
Can I compare files with Windows line endings?
Yes. CRLF and CR are normalized to LF before comparing, so a file edited on Windows and another on Linux do not show up as completely different.