localStorage vs sessionStorage vs Cookies: When to Use Each

Three browser storage mechanisms, each with different lifetimes, scopes, and appropriate uses. Here's when to reach for each. Overview Feature localStorage sessionStorage Cookies Capacity ~5–10 MB ~5 MB ~4 KB Expires Never (until cleared) Tab/session close Set explicitly Sent with requests No No Yes (automatically) Accessible from JS Yes Yes Yes (unless HttpOnly) Scope Domain Tab + domain Domain (configurable) localStorage Stores data with no expiry. Persists until the user clears it or the site