How is Spanbox different from Beeper? Does it use a bridge/server or run the real apps?

That's the core difference. Beeper routes your chats through bridges, your messages pass through their (Matrix) servers to be unified, which is clever but means a third party sits in the middle. Spanbox doesn't do that. It runs each app's real web session locally on your machine, the same login you'd use in a browser, and just puts them all in one window. Nothing is relayed through a Spanbox server, because they don't run one that can see your messages. So it's less 'magic bridge', more 'all your real apps in one tidy shell', which is the trade-off: Spanbox needs each app to have a web version, but nothing leaves your device.

Beeper = bridge through their servers (great for iMessage-on-Android type tricks). Spanbox = the actual app sessions running locally, no middleman. If privacy/local-first matters most to you, that's the deciding line.

The flip side of Spanbox's approach: if an app has no web version (Signal, for now), Spanbox can't span it yet, whereas a bridge can sometimes. So it depends whether you value local-first or maximum app coverage.

Been on both. Beeper's bridges occasionally lag or drop because there's a relay; Spanbox feels like using the real app because it IS the real web app, just docked in one window. Different philosophy.