About Diff Checker
Comparing two versions of a document by eye is slow and error-prone. This diff checker aligns both texts using a longest-common-subsequence algorithm, the same approach used by version control systems, then marks each line as added, removed, or unchanged.
How to use
- Paste the original text on the left.
- Paste the changed text on the right.
- Toggle case or whitespace sensitivity if needed.
- Review the highlighted additions and deletions.
Frequently asked questions
What does "ignore whitespace" do?
It collapses runs of spaces and tabs and trims each line before comparing, so reindentation or trailing spaces are not reported as changes.
Can I compare code?
Yes. Comparison is line-based and language-agnostic, so it works for source code, configuration files, logs, or prose.
Is there a size limit?
Each side is capped at 1,500 lines. The comparison builds a table proportional to the product of both line counts, so very large inputs would exhaust memory.