Your bank data and Carlo

Carlo offers two ways to connect a bank. Both are read-only, and both keep your transaction history encrypted. The difference is where the credential that can access your bank data lives.

Carlo never gets your banking password. Signing in happens with your bank, and what comes back is a credential for reading transactions — not your username or password.

Your transactions are encrypted on your device before they are stored with Carlo. Carlo's servers hold encrypted financial data that Carlo cannot read.

Carlo's bank connections are read-only. Carlo cannot transfer money, make payments, or move funds.

Plaid — easier, and far more banks. Plaid is the simplest way to connect and supports many more institutions. The tradeoff is that the connection is kept open by a credential stored on Carlo's servers, which is what lets Carlo ask Plaid for new transactions on your behalf. Carlo still never receives your bank password, and the transactions Carlo keeps are encrypted with your key — but you are trusting Carlo's infrastructure to protect the credential that keeps the connection open. This is the model most financial apps use, because it makes bank connections much easier and more reliable.

SimpleFIN — less trust in Carlo's servers. You get an access token directly from SimpleFIN and add it to Carlo on your phone, and it stays there. Carlo does not store your SimpleFIN access credential on its servers, and is built so it cannot. There is no server-side credential capable of reaching your bank on its own.

You also choose which accounts it covers. One SimpleFIN connection can reach every bank you have linked there, so Carlo asks you to pick — and then only ever requests those accounts. An account you did not pick is not filtered out after the fact; it is never sent to your phone.

The tradeoffs are real: SimpleFIN charges separately from Carlo and setup is more manual. Carlo offers it because some people would rather accept that inconvenience than place the credential for their bank on someone else's servers.

Put simply: Plaid minimizes friction. SimpleFIN minimizes how much you have to trust Carlo's infrastructure.

Whichever you choose, Carlo uses bank access only to retrieve transactions, cannot move your money, and stores what it keeps encrypted with your key. Disconnecting a bank ends future access; what you have already recorded stays until you delete it, and deleting your account removes everything Carlo holds. One consequence is worth being clear about: your bank data is encrypted with your key like everything else in Carlo, so if you lose your recovery code, Carlo cannot decrypt your financial history for you.