File & Text Diff Checker

About File & Text Comparison

Spotting what changed between two versions of a file by eye is slow and unreliable, especially across long documents, source files, logs, or configuration exports. A diff checker compares the two inputs line by line using a longest-common-subsequence algorithm — the same core technique behind git diff and code-review tools — then reports exactly which lines were added, which were removed, and which were modified. This makes it easy to review edits, audit config drift, verify exports, or confirm what a change actually touched.

How to Read the Diff:

• Added (+): Lines present in the right (changed) input but not in the left (original).
• Removed (-): Lines present in the left input but missing from the right.
• Changed (~): In the side-by-side view, a removed line paired with an added line at the same position — shown side by side so you can compare the old and new text directly.
• Unchanged: Identical lines, dimmed for context so you can see where changes sit within the file.

Options:

• Ignore case: Treats ERROR and error as the same line.
• Ignore whitespace: Collapses runs of spaces and trims each line, so re-indentation or trailing spaces are not flagged as changes.

Common Use Cases:

• Config Review: See exactly what changed between two versions of a settings or environment file.
• Log Analysis: Compare log output before and after a change to isolate new errors.
• Content Editing: Track edits between two drafts of an article, contract, or document.
• Code Review: Compare two versions of a script or source file without a full version-control setup.

Load files directly or paste text, then switch between side-by-side, unified, and changes-only views. Because the comparison runs entirely client-side, you can safely diff sensitive files — nothing is uploaded, stored, or tracked.