Yeah those guys are right, it really doesnt sync fast enough to rely on for a speed run. Better to be safe so you dont end up with two of everything. I usually do this instead:

• Use a shared Note or AnyList to track items first
• Pick one designated person to actually hit checkout
• Check your subtotal twice before paying to catch doubles Its way less stressful than hoping the app catches up.

Ngl it doesnt sync live very well. I tried once and things got messy... just refresh the app manually every few minutes to stay safe and avoid double orders.

Basically you cant do it in real-time because the backend isn't built on web sockets or any data streaming protocol, so it wont push updates to another device instantly. I remember trying to sync a huge grocery run for a wedding once and the concurrency issues were a nightmare because the app relies on manual GET requests to fetch the latest cart state from the server. Tbh if you both add things at the same millisecond, the database might even throw a conflict error or just overwrite one of the items since it lacks robust optimistic locking for guest sessions.

• Database lag is usually around 5 to 10 seconds per session
• Local cache doesnt invalidate automatically without a UI trigger
• Multiple sessions on one login often cause token collisions Honestly you should just use a shared list app instead. Go with any of those dedicated grocery list brands like AnyList, you cant go wrong there. They actually handle the sync properly.