Code difference checker

Compare two files line by line.

On your device · No account

Privacy details

Code difference checker processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

Copy link includes the inputs you choose to share in the address. Anyone with that link can reopen them. Files and generated results are excluded. Password and key tools share settings only.

Your input

Changed code

Options and local file

Open a text file on this device

Optional settings apply only to this tab.

Your result

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.

Links include your inputs and settings. Anyone with the link can see them, so leave out private text. Files and generated results are left out; random draws run again.

Keyboard shortcuts

Updated 2026-09-20

Code difference checker explained

Compare two code or text files using a longest-common-subsequence line diff. Added lines start with plus, removed lines with minus, and unchanged lines remain as context. Spaces inside lines are significant.

Next: JSON formatter

A worked example

Changing return 1; to return 2; produces a removed old line and an added new line. A line that stays identical remains unmarked.

Before you use the result

This compares text, not program behavior. CRLF and LF line endings are normalized. The output is a readable diff, not a patch with file headers that can be applied automatically.

Cite this page

Citation style

ToolOctopus. “Code difference checker.” Updated 2026-09-20. https://tooloctopus.com/code-difference-checker.

Add an access date if your instructions require one.

Citation formatting uses citeproc-js by Frank Bennett and Citation Style Language styles. Licence and source code.