Paste into Original and Revised, import UTF-8 text files, or drop a file onto either editor. Changes appear as you type, with line and character highlights. Use Split to edit both texts, or Inline for a read-only comparison. On a phone, switch between Original and Revised to edit, then choose Inline to review.
Move between change groups with the arrows or F7 and Shift+F7. In desktop Split view, the arrow between a changed block copies that block from Original to Revised. Undo with Ctrl/⌘+Z, or use each editor’s menu. Swap exchanges both texts. Imports, swaps, and merges stay undoable while this tab is open.
Find opens search in the last active editor. Ctrl/⌘+F also opens search; regular expressions, case matching, whole words, and replacement are available in editable views. Options includes line wrapping, visible spaces and tabs, collapsed unchanged lines, comparison filters, and unified .patch export. Each editor’s menu also has Copy and Download.
Filters create a read-only preview. Ignore case converts both previews to lowercase using JavaScript’s Unicode lowercase mapping, without locale-specific collation. Trim line edges removes leading and trailing whitespace on each line; spacing within a line remains significant. Ignore blank lines removes whitespace-only lines. Preview line numbers refer to this filtered text. Your editable originals, downloads, and patch exports stay unfiltered.
Comparison, file reading, search, and patch creation happen in your browser. Text is not uploaded to this site, placed in a share link, or saved to browser storage. Refreshing or leaving this page clears the workspace. Download text you want to keep. You do not need an account.
Compare plain text, source code, JSON, XML, CSV, logs, and other UTF-8 text. Rich documents, PDFs, images, binary files, and other encodings are not supported. Files must be smaller than 1 MB, and each editor accepts up to 200,000 UTF-16 code units and 10,000 lines. Windows CRLF and classic CR line endings are normalized to LF on input and export; this is a text comparison, not a byte comparison. A missing final newline remains a difference.
Editors render only the visible document area. Detailed comparison has a time and complexity budget; very different texts may show larger change groups with a notice. Those groups still cover the differences, but are less granular. Patch creation runs separately from the page and stops with an error if it exceeds its limits. It never downloads an incomplete patch.
The downloaded unified diff transforms Original into Revised, with three context lines around each change. It always uses the unfiltered editor texts and LF line endings. Review the file names before applying it to a repository. Use each editor’s Download action if you need the complete text instead.