Diff checker · Guide
Diff Checker Online: Compare Two Texts
A diff checker compares two blocks of text and highlights the differences line by line. This guide explains how line diffing works and where it is most useful.
How line diffing works
The checker lines up the two inputs and marks each row as unchanged, changed, added or removed. Seeing the changes coloured and aligned makes it obvious what moved between two versions.
It runs in the browser, so the texts you compare — configs, drafts, generated output — stay on your machine.
When to use it
Comparing two config files, reviewing an edited paragraph, or checking that generated output matches a baseline all become quick visual tasks instead of tedious manual reads.
Frequently asked questions
Is the comparison line-based or character-based?
It compares line by line, which is ideal for code, configs and structured text. Lines that differ are highlighted so you can see exactly which rows changed.
Ready to try it?
Open the free browser-based Diff checker and apply what you just read — no sign-up, runs locally.
Open the Diff checker tool