Text Diff Checker

The checker compares the two texts line by line using the Myers diff algorithm — the same approach used by Git and most professional diff tools. It finds the longest common subsequence of lines, so a single inserted paragraph shows up as one addition instead of marking everything after it as changed. When a line was edited rather than added or removed, the changed words inside it are highlighted so you can spot a one-word difference in a long sentence at a glance.

Reading the output

Green rows with a + exist only in the changed text; red rows with a − exist only in the original. A red row immediately followed by a green row is an edit — the brighter highlights inside mark exactly which words differ. With Collapse unchanged lines on, long identical stretches fold into a divider so the differences stay in view.

Options

Ignore case treats “Hello” and “hello” as identical — useful for case-insensitive formats. Ignore trailing whitespace (on by default) stops invisible end-of-line spaces from flagging otherwise identical lines, a classic source of noisy diffs when text has passed through different editors. Swap sides reverses the direction of the comparison in one click.

What it's for

Comparing two versions of a contract clause, checking what an editor changed in your draft, verifying a config file against a known-good copy, reviewing AI-revised text against your original, or confirming that two “identical” exports really are identical. If you work with code, your editor's built-in diff is still the right tool — this one is for the quick, no-setup cases.

Privacy

The comparison runs entirely in your browser. Neither text is sent anywhere, saved, or logged — compare confidential drafts freely.