About comparelists.io

A simple tool to compare two text lists in your browser without uploading your data anywhere.

Why It Exists

I built CompareLists because I got tired of opening Excel or writing one-off Python scripts just to see what changed between two spreadsheets or database exports.

Spreadsheet formulas like VLOOKUP work, but they take too many steps for quick checks. Most online comparison sites are cluttered with ads, require an account, or send your clipboard data to an external server.

CompareLists provides a quick alternative: paste two lists, pick your options, and see the differences immediately.

Privacy note: There is no backend database attached to this tool. When you paste your lists, all comparison math runs locally inside your browser tab.

Features

Shows Only in A, Only in B, and In Both side by side so you do not have to switch views.
Splits items by line break, comma, tab, semicolon, pipe, or custom regular expressions.
Quick options to trim whitespace, drop duplicates, or ignore uppercase and lowercase.
Adds prefixes or suffixes to format results for SQL queries and code.
Works offline as an installable Progressive Web App (PWA).

Minimal and Fast

The site is built with plain HTML, CSS, and vanilla JavaScript. There are no frontend frameworks or heavy tracking scripts, just a lightweight utility that loads immediately.

Created by Jimmy

CompareLists was designed and developed by Jimmy (@Jimmy_Ships on X) as a fast, private, distraction-free utility. Having spent years wrestling with clunky spreadsheet formulas and ad-bloated diff checkers, Jimmy built CompareLists to run completely client-side in RAM—ensuring sensitive customer lists, database identifiers, and emails never leave your browser.

Follow @Jimmy_Ships on X to stay updated with new features, give feedback, or say hi.

Page last updated: September 2026

Have feedback, found an edge case, or want to suggest an option? Get in touch.