Keep the original unchanged
Copy the earlier draft into the first field and the revised draft into the second. Avoid editing either copy while comparing; this gives you a stable baseline for release notes, configuration, translations, and policy text.
Read additions and removals
Run the Text Difference Checker to mark unchanged, added, and removed lines. A replacement is represented as a removed line plus an added line. If you reverse the two inputs, the direction of those labels also reverses.
Know what a line diff can tell you
This tool compares exact lines of plain text. Whitespace changes, punctuation, and line breaks count as changes. Moving a paragraph can look like a deletion and an addition. It does not understand programming syntax, document formatting, images, or binary files; use a format-aware diff when those details matter.
Make large reviews manageable
If a very large comparison reaches the tool limit, split the material into corresponding sections and compare each pair separately. Keep headings or other stable context around each excerpt so you can tell where a change belongs.
Review sensitive material carefully
The comparison runs in your browser and the site does not upload the text. Still, treat the two drafts as sensitive on a shared device: close the page when finished and avoid copying secrets into a public or shared environment.