> For the complete documentation index, see [llms.txt](https://developer.paywall.one/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.paywall.one/payment-orchestration-integration-document/payment-service/18.-batch-processing-method/3.-refund.md).

# 3. Refund

**Batch:** You can submit a transaction initiated via a batch payment order, along with its MerchantUniqueCode, to the Paywall APIs to process refunds for all transactions under that batch payment.

**List:** You can send payments identified by your MerchantUniqueCode values (which may be from batch or single transactions) as a single list to Paywall’s batch refund service. This allows you to complete refunds for all transactions with a single API call and receive a single callback notification from Paywall in response.