What's more persistent, LocalStorage or PHP Sessions?

Question

• Let's say 100% of my users are on local storage enabled browsers.
• using either mobile or desktop devices
• to store a 50 character string (that contains no sensitive info)
• considering, browser updates, cache restrictions etc...

Which is most likely to still hold this value 100 days later, long-expiry sessions or localstorage?

Answer 1

You have complete control over how long a session is alive on your server.
You have no control whatsoever over anything that goes on on the client. That includes LocalStorage and the session cookie needed for the session. Either way, it entirely depends on the client, there's no prediction you can make here either way.