Using browser.storage.sync vs storage.local in Firefox Extensions: When to Use Each

Using browser.storage.sync vs storage.local in Firefox Extensions: When to Use Each Firefox extensions have two main storage options: browser.storage.sync and browser.storage.local . Picking the wrong one leads to frustrating UX. Here's how to think about it. The Core Difference storage.sync storage.local Synced across devices Yes (via Firefox Sync) No Quota 100KB (8KB per item) 10MB Requires Firefox Sync Yes, to actually sync No Falls back gracefully Yes (local if not synced) N/A storage.sync: