Screenshots
Replace A and B, drop two images onto the canvas, or paste a screenshot. The first pasted image replaces A; the next replaces B. Swipe the divider, blend the images, highlight differences, compare side by side, or use slow blink. Zoom with the wheel or a pinch. When zoomed, drag away from the divider to pan.
Pixel comparisons are not semantic or perceptual judgements. Fonts, compression, antialiasing and alignment can create differences. Unequal image sizes are not stretched. Blank areas outside an image count as different from visible content. Color is compared after compositing transparency onto white; alpha-channel differences also count.
For responsive on-device processing, unaligned working images are limited to a shared 2,400-pixel longest edge and 4-million-pixel bounding canvas. Larger inputs are downsampled together at the same scale. Alignment may expand the canvas, up to 8 million pixels. Metrics and coordinates refer to the working canvas; exported PNG review sheets contain scaled views. GIFs use a single frame; SVG and PDF imports are not supported.
Text
Paste two versions or open UTF-8 text files. Changes update after typing. Use “Ignore whitespace” to trim and collapse whitespace within each line; blank lines still count. “Ignore case” uses Unicode lowercase comparison. Line endings are normalized to LF; trailing newlines remain significant. Word highlights inside replacement lines follow the raw text.
Your files stay yours.
No uploads, analytics, remote fonts, external libraries or API keys. Files remain in memory by default. Optional “Remember this session” uses this browser’s IndexedDB, not cloud sync. Exported session files and review reports contain the input content, including potentially private material. Clear a remembered session from the Session menu before using a shared device.
This app can run as a single HTML file or be served from your own site. Browser policies may restrict storage or downloads. Storage errors are shown. A download notification means the browser was asked to save a file; check your downloads to confirm it finished.
Keyboard
1–5Switch image view
FFit canvas
+ / −Zoom in / out
SpaceHold before image
[ / ]Previous / next change
Ctrl EnterCompare text
Ctrl SOpen session menu
EscClose a dialog