# Payments

With our investment API, we simplify the administration of cash payments and instant investments through automation.

* [Setting up a mandate](/products/byol/guides/payments/mandate_setup/mandate_setup_intro)
Setting up a mandate is the first step to enable automatic funding of a cash balance on our platform. With a mandate, a user authorises Upvest to collect payments on their behalf.
* [Direct debit funding](/products/byol/guides/payments/direct_debit/direct_debit_intro)
A direct debit funding is a process which results in an increase of the cash balance from the user's IBAN specified on their mandate.
* [Cash balances](/products/byol/guides/payments/cash_balances/cash_balances_intro)
Cash balance refers to the portion of our user's investment portfolio assets that reside in cash. Fundings, withdrawals, and all order processes affect the cash balance of an account group.
* [Reference bank accounts](/products/byol/guides/payments/reference_accounts/reference_accounts_intro)
Learn how to register and manage reference bank accouns for a user on the Investment API.
* [Top-ups](/products/byol/guides/payments/top_ups/top_ups_intro)
With top-ups, users can seamlessly invest in assets without having to wait for their funds to settle, making investing more efficient and convenient.