Browser Storage for Extension Developers: localStorage vs. browser.storage.local

When building a Firefox extension, you have two main options for client-side storage. Choosing wrong will either lock you out of sync features or break your extension on private browsing. Here's the practical difference. The Short Answer Use browser.storage.local . Not localStorage . Not sessionStorage . Not indexedDB (unless you have very specific needs). Here's why. Why Not localStorage? In a regular web page, localStorage is straightforward. But in an extension: It doesn't work in background