Paste into A and B, or drop a file onto either box, then press Compare. Editing a text while the comparison is open re-runs it as you type. Edit text goes back. Both boxes are numbered down the side, and the numbers follow wrapped lines, so a line number in the comparison points at the same line in the box you typed it into.
Removed lines are red on the left, added lines green on the right, and a changed pair is marked
≠ with the differing words highlighted inside the line. The striped cells are padding
where one side has no matching line. The strip down the right edge maps every change in the whole
document — click it to jump.
Side by side aligns the two texts line by line. Inline merges them into one running text, which reads better for prose; choose whether it compares by word or by character.
These control what counts as a difference, not what gets displayed. Turn on Nikud & te'amim to compare a pointed text against a plain one, or Trailing space to stop invisible whitespace showing up as changes. The badge shows how many are active.
A regular expression. Any line matching it is left out of the comparison entirely and shown dimmed
with a ~ marker — useful for timestamps ^\d{4}-\d\d-\d\d, comments
^\s*//, or regenerated IDs. The pattern matches anywhere in the line unless you anchor
it with ^. The box turns red if the pattern is invalid.
The menu on each box rewrites that text in place — trim, sort, remove duplicates, strip nikud, strip HTML tags, normalize Unicode. This changes the text itself, unlike the ignore options.
Unified diff is a standard patch file. Changed lines only is a plain list for pasting into an email or a ticket. HTML report is a self-contained page of the side-by-side view.
Single-key shortcuts only fire when the cursor is not inside a text box, so they never interrupt typing. The arrow keys move between changes in the comparison view; scroll with the mouse, Space, or Page Up and Page Down.
Changes how the comparison looks, not what it finds. Each option shows a live sample, so pick the one that reads best. Change marks sets how differing words are picked out inside a line: a filled highlight, removed text struck through against added text underlined, bold letters, or nothing at all if you only want the line-level coloring. Colors offers orange and blue instead of red and green for easier reading if red and green are hard to tell apart, or ink only for printing and photocopying, which uses two weights of gray. In the side by side view, position already tells deletions from additions; if you use ink only with the inline view, pair it with strike and underline so the two stay distinguishable.
Everything runs inside this page — your text is never uploaded, and it is never saved. Your settings — theme, ignore filters, the regex, and the view and display choices — are kept in this browser so they are still set the way you left them next time. Reset saved settings in the Display menu clears them.