Diff Checker | Text Comparison Tool

How do I compare two versions of code or config files online?

Paste the original text into the left panel and the modified text into the right panel, then click Compare. The tool performs a line-by-line diff and highlights removed lines in red (prefixed with -) and added lines in green (prefixed with +). A summary bar shows total added, removed, and unchanged line counts.

Is the diff checker safe to use with proprietary code or secrets?

Yes. The diff runs entirely in your browser using JavaScript. Neither text block is sent to any server. You can safely paste source code, configuration files, environment variables, or any confidential text without it leaving your device.

What is the difference between inline view and side-by-side view in a diff tool?

Inline view displays both the original and modified lines in a single column with color coding, which is compact and easy to scroll. Side-by-side view places the original and modified versions in two columns aligned by line, making it easier to compare matching lines. Side-by-side is more useful when changes are localized; inline is better for reading a large number of sequential changes.

Can this diff tool compare files rather than just pasted text?

The current version accepts pasted text only — there is no file upload button. For comparing actual files, copy and paste the file contents into each panel, or use a local tool like diff, git diff, or VS Code’s built-in diff editor, which have no size constraints and work directly on the filesystem.

Does this tool do word-level or character-level diffs?

The diff operates at the line level, consistent with the standard Unix diff algorithm. Lines that are identical appear unchanged; any modified line is shown as a deletion of the old line and an insertion of the new line. Word- or character-level highlighting within a changed line is not currently displayed, which can make single-character changes harder to spot in long lines.