What algorithm powers the diff?

We use a longest common subsequence (LCS) algorithm implemented in plain TypeScript, run entirely in your browser.

Can I ignore case or whitespace differences?

Yes, both options are available and update the comparison instantly.

What's the difference between unified and side-by-side view?

Unified shows one combined list with +/- markers; side-by-side shows original and changed text in two columns.

Diff Checker

Compare two texts line-by-line with an LCS diff.

Works Offline

Privacy First

No Login

No API

Original text

Changed text

Diff result

Line-by-line comparison using LCS

View

Ignore whitespace Ignore case

Added

Removed

-0

Unchanged

About the Diff Checker

Compare two blocks of text line by line using a longest common subsequence algorithm, viewable as a unified or side-by-side diff, with options to ignore whitespace and case differences.

Examples

Compare lines

line1\nline2

Output

line1\nline2 (changed)

Related tools

Acronym & Initials Generator

Text & String

Generate acronyms, initials, or camelCase from phrases.

ASCII Art Text Generator

Text & String

Turn text into a big ASCII banner using letters and numbers.

Case Converter

Text & String

Convert text between 11 different letter cases.

Character Counter

Text & String

Count characters and bytes with limit presets.

Column Aligner

Text & String

Align delimited text into padded, readable columns.

Find & Replace

Text & String

Search and replace text with plain or regex matching.

Frequently asked questions

Version 1.0.0 · Updated 2026-08-06 · Runs entirely in your browser