Looking at the code, it looks like they are not logging into MongoDB/Realm async, they are just checking if it is done, then reloading the page if not. con

Looking at the code, it looks like they are not logging into MongoDB/Realm async, they are just checking if it is done, then reloading the page if not. const user = app.logIn(credentials); export const client = num_users===0 ? // wait for 1 second before reloading the page setTimeout(() => { window.location.reload(); }, 350) : app.currentUser.mongoClient("mongodb-atlas") (which coincides with loads of realm users in localstorage if it continues to reload) This https://www.mongodb.com/docs/realm/web/authenticate/ https://www.mongodb.com/docs/realm/web/authenticate/ shows how to login whilst waiting for a user to be created. Edit: @aditiyadav Hope that doesn't come across wrong, just pointing out where the problem could be :)