Nice to see a diff tool aimed squarely at everyday copy-paste comparisons instead of trying to be an IDE plugin. A couple pieces of feedback from a habitual diffchecker user:

• Client-side diffing is great for privacy, but it might help to call out the file-size limits so people don’t assume they can drop a 50MB log in there. Even a small progress indicator when the diff is running would make the “nothing’s happening” moment less confusing. • Dark mode or at least a higher-contrast theme would be appreciated—most of us are jumping over from code editors that are already dark.

Curious if you’re considering side-by-side character-level highlighting like Kaleidoscope/VSCode’s inline mode. That’s the one feature that usually pushes me back to the heavyweight tools. Either way, thanks for putting another option out there.