Set up Dwolla mass payment to disburse funds to multiple verified customers in a single API call and handle partial failures

Steps

1. Ensure all recipient Dwolla customers are verified and their funding sources are added and verified (via micro-deposits or Plaid instant verification)
2. Construct the mass payment request body with the _links source funding source and the items array, each item specifying a destination funding source and amount
3. POST to the mass payments endpoint and capture the Location header containing the mass payment resource URL
4. Poll the mass payment resource and each mass payment item resource to monitor individual transfer statuses as they progress from pending to processed
5. Handle items in failed status by reading the failure reason and deciding whether to retry with a new mass payment item or alert the customer
6. Reconcile each successful item against your internal payout ledger using the Dwolla transfer resource ID