Running an Expo SDK 57 app in Expo Go? You now need to be logged in on both ends

You scan the QR code like you've done a hundred times before, npx expo start is running, the terminal looks fine, but the app on your phone just sits there with an error instead of loading your project.

Here's what changed: Expo Go on iOS has been updated in the App Store to support Expo SDK 57, and along with that update comes a new requirement. To run an SDK 57 project in development mode, you now need to be logged in to both the Expo CLI in your terminal and the Expo Go app itself, using the same account on both sides.

This is live now for the latest Expo Go on iOS. Android is getting the same treatment later, and it doesn't touch simulator builds or development builds at all.

What you'll see

If either side isn't logged in when you scan a QR code (or tap a dev server address on the Home tab), Expo Go shows you an error telling you exactly what's missing: