I believe these companies are already doing it and charging a fee because they provide compliance and have required MSB licenses.

1. https://plaid.com/products/transfer/

2. https://www.flinks.com/products/pay

3. https://paytm.com/online-payments

OpenSpend should be open-source and free, unlike the companies mentioned above.

The idea is not only to provide the software but also legal templates like cancellation policy, refund policy, dispute resolution, etc., for different jurisdictions.