Question 1

What is a text diff checker?

Accepted Answer

A text diff checker is a tool that compares two blocks of text and highlights the differences between them — showing which lines or words were added, removed, or unchanged. It is commonly used by developers to review code changes, writers to compare document revisions, and anyone who needs to spot edits between two versions of text.

Question 2

How does a diff algorithm work?

Accepted Answer

Most diff tools use the Myers diff algorithm, which finds the shortest edit script (minimum number of insertions and deletions) needed to transform one text into another. It computes the longest common subsequence (LCS) of the two texts and marks everything outside the LCS as either an addition or a deletion.

Question 3

What is unified diff format?

Accepted Answer

Unified diff format is a standardized text format for showing differences between two files. It displays a few lines of context around each change, with added lines prefixed by + and removed lines prefixed by -. It is the format produced by git diff and patch commands and is widely used in code reviews and version control systems.

Question 4

Can I compare code files with this diff tool?

Accepted Answer

Yes. Paste the contents of any two code files into the two panels and the tool will show a line-by-line and word-level diff. All processing happens in your browser, so your code is never sent to any server.

Question 5

What do the green and red colors mean in a diff?

Accepted Answer

Green highlights indicate lines or words that were added in the second (new) version of the text. Red highlights indicate lines or words that were removed from the first (original) version. Unchanged lines are shown without any color highlight.

Text Diff Checker

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