Is there a copy of my journal outside the app?

Two, if you use the desktop app. Every snapshot also writes a full file to Documents/TradePerformance/Backups, and any snapshot can be downloaded as JSON with Download.

The local file is the complete, uncompressed account, written before any differencing — it needs nothing else to read it, and it survives losing access to the service entirely. The stored snapshots survive losing the laptop. Neither substitutes for the other, which is why both exist.

The local copy is written only by the desktop app, because a browser cannot write to your Documents folder. In a browser the equivalent is the Download button on any snapshot row.

Like the stored snapshots, the file leaves out your connections, licence, devices and profile — so a backup file that ends up somewhere it should not carries your trading record, not your broker credentials.