Description from extension meta
Chrome extension to prevent duplicate game purchases
Image from store
Description from store
Stop Before You Buy: Never Buy a Game You Already Own
Stop Before You Buy is a free Chrome extension that prevents you from accidentally purchasing games you already own on other platforms. By integrating with your unified GOG Galaxy library, this extension provides a clear warning on store pages if a game is already in your collection, saving you money and hassle.
The extension works by checking the games you are Browse on popular online game stores against a local copy of your game library. When it detects that you already own the game, it will display a notification, as seen in the screenshots.
To build its database, "Stop Before You Buy" relies on importing CSV file generated from your GOG Galaxy client. GOG Galaxy is a free application that allows you to connect and manage all your games from different platforms like Steam, Epic Games Store, Ubisoft Connect, and more, all in one place.
How to use
1. Install this extension
2. Install GOG galaxy and sync all your accounts (Steam, GOG, Epic)
3. Use this script (https://github.com/AB1908/GOG-Galaxy-Export-Script) to export the library to a CSV file
4. Import the CSV file in the extension