Is my data separated from other businesses?

Every organization runs on its own database. Your customers, documents and files are physically isolated — no other organization can query them, which is a stronger guarantee than filtering rows by an account column. The database is created for you when you sign up, and it is dropped when you close the account.

Isolation is enforced at the connection, not in application code. Every request looks up your organization and repoints the database connection at your own schema before any query runs, so a query written against the wrong organization has no rows to find rather than the wrong rows.

Your login belongs to exactly one organization. There is no account that spans several organizations and no way to switch between them from inside the app.