SDK - Prevent Double Payments - Request Network V3 with 100% double payment prevention using onchain invoices and onchain expected amounts

[MantisClone]

Problem

At a smart contract level, the reference-based payment proxies don't prevent Double Payments.

Solution

Write a Request Network V3 that stores invoice expected amounts onchain so that the balance of a request can be checked at the smart contract level and overpayments can be 100% prevented.

Considerations

1. How to handle multi-chain? What if the invoice (and expected amount) is stored on Gnosis, but payment is on Polygon?

Ideas

• Crosschain message bridges
• LayerZero