Question 1

What diff algorithm does this tool use?

Accepted Answer

The tool uses the Longest Common Subsequence (LCS) algorithm, the same foundation used by Unix diff and Git. It compares files line by line, identifies the longest sequence of unchanged lines, and marks the rest as additions or deletions. This produces minimal, meaningful diffs without excessive noise.

Question 2

What is the difference between side-by-side and unified view?

Accepted Answer

Side-by-side view shows the original on the left and the modified version on the right, with matching lines aligned. Unified view interleaves removed lines (shown in red) and added lines (shown in green) in a single column, similar to git diff output in a terminal.

Question 3

Does the language selector affect the diff output?

Accepted Answer

The language selector is for your reference only. It labels the diff but does not change how the comparison is performed. All diffs are done at the line level regardless of language. Syntax-aware token-level diffing is not currently supported.

Question 4

How are line numbers shown in the diff?

Accepted Answer

Each side shows its own sequential line numbers. In side-by-side view, the left panel numbers the original file and the right panel numbers the modified file. Empty placeholder rows for padding do not get line numbers.

Question 5

Is there a size limit on the code I can compare?

Accepted Answer

There is no hard limit, but very large files with thousands of lines may take a moment to diff since the LCS computation is O(m*n). For typical code snippets, functions, or configuration files the diff is instant.

Code Diff

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Compare config files

Spot regressions

Code diff tool with line numbers

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