Diff Checker: Frequently Asked Questions

Yes. The diff checker compares any plain text, including source code in any programming language. For syntax-highlighted code comparison, it shows line-level and character-level differences clearly.

Not directly — the diff checker works with plain text. Copy and paste the text content from your Word documents into the two panels. For rich-text comparison including formatting changes, Word's built-in Track Changes or Compare Documents feature is better.

Green lines (with a + sign) are additions — text that exists in the right panel but not the left. Red lines (with a - sign) are deletions — text that exists in the left panel but not the right. Unchanged lines appear without colour.

The diff checker handles large texts well since it runs in your browser. Very large texts (hundreds of thousands of lines) may be slow to process. For extremely large files, a command-line diff tool is more appropriate.

The diff checker normalises line endings (converting Windows CRLF to Unix LF) before comparing, so differences in line endings do not show up as false positives.

You can paste the contents of any plain text file — code files, CSV, JSON, Markdown, configs — directly into the panels. Direct file upload for binary comparison is not supported.

The diff uses the Myers diff algorithm, the same algorithm used by Git. It finds the shortest edit script (fewest additions and deletions) that transforms one text into the other, which produces the most human-readable diff output.

The diff checker does not save diffs or generate shareable links. Copy the output or take a screenshot to share results. Your texts never leave your browser.