A unique aspect of Column is we have decoupled accounts and account numbers. You can think about each account number as a pointer to a bank account. Historically, as banks were tied to legacy cores, their systems linked an account number to a bank account one to one. You can have infinite account numbers point to a single bank account. Our approach allows you to create account numbers at will. Column does not ledger at the account number level, only the account level. So, for example, if one account has five account numbers, you will see aggregated transaction activity and balances across all five account numbers at the account level.
We're planning on allowing you to set restrictions on these account numbers. These may include send-only or receive-only restrictions, transaction size or total volume limits, or restrictions on name/sender/receiver. We're eager to hear about what you want - we think this is an extremely powerful concept and are excited for what you build!