How to use it
Paste the original into the left box and the changed version into the right. The comparison runs as you type, so you can edit either side and watch the result change.
Copy puts the result on your clipboard and confirms it did. Download saves it as a file, which is the easier route when the output is long enough that selecting it by hand is a nuisance. Clear empties the boxes and puts the cursor back where you need it.
Where a sample button appears, it loads a small realistic example. It is there so you can see what the tool expects before pasting your own material, which is quicker than reading a description of the input format.
Keyboard and mobile
The text areas are ordinary form fields, so every shortcut your system already has works: select all, undo, redo, and paste without formatting. Tab moves between the panes and the controls in the order you would expect, and every control is reachable without a mouse.
On a phone the panes stack rather than sitting side by side, and the text areas grow to a comfortable height. Spellcheck and autocorrect are switched off in them, because a tool that silently capitalises your text compare input is worse than useless.
If something looks wrong
When the result is not what you expected, the message under the boxes is the first thing to read. It reports what happened rather than a generic failure, so a malformed input names the line to look at and a successful run reports what it did, such as how many lines it kept or how many replacements it made.
A count of zero is informative in itself. It usually means the input did not contain what you thought it did, most often because of capitalisation or an invisible trailing space, both of which are far more common in pasted data than people expect.
Nothing is corrected silently. If the input cannot be handled, the output is left empty and the reason is stated, rather than a partial result being returned that looks plausible and is wrong. A tool that guesses is worse than one that says it could not.
