# Highlight the power of “rounding up” payments by pulling transaction history with the US Open Finance APIs
source: https://developer.mastercard.com/blog/highlight-the-power-of-rounding-up-payments-by-pulling-transaction-history-with-us-banking-apis/index.md

Authors: Derek Humphreys. Description: There are many value-added services you can provide once you have access to a customer's transaction history. One I particularly like is how you can use this data to showcase the power of rounding up transactions and taking the "small change" to save it or maybe donate it to charity. This can be a difficult feature to sell to prospective customers who don't appreciate how all these small transactions can quickly add up. I should quickly explain what I mean by Open Finance. Simply put, it allows the owner of a bank account to grant third-party access to that bank account. They can control what accounts can be seen, how long that access can be granted for and for what purpose. The bank account owner (your customer) feels safe doing this because they are authenticating directly with their bank, using their online banking credentials, confident that the third party won't see or store them. The beauty of the US Open Finance API is that it handles the connections to all the banks (10,000+ US connections), provides a secure dialog so the account holder can authenticate, and caches the financial data so when you execute a query it comes back quickly (not having to make a round trip to the bank every time). In the next video I will show you how to use the US Open Finance API to pull the past 6 months of transactions (and up to 24 months) so you can then apply a rounding up feature to show how much the customer could have saved or donated over that timeframe. If you haven't already done so, check out our getting started blog video that will walk you through the steps to create your account, get your sandbox keys and get connected to the US Open Finance APIs here. How to aggregate transactions like this is also documented here.