Refund Protocol is a smart contract developed by Circle Research that enhances the security and flexibility of stablecoin payments by introducing non-custodial escrow and onchain dispute resolution for ERC-20 transactions. This system allows for refunds, lockups, and mediated resolutions without relying on a centralized third party. The protocol enables a third-party arbiter to mediate disputes without taking direct custody of funds, allowing disputes to be resolved transparently and securely. Key features include lockup periods, arbiter-mediated refunds, and early withdrawals, with offchain agreements between parties to ensure fair procedures. While the protocol offers a solution to the lack of refund mechanisms in stablecoin payments, it faces challenges such as managing potential malicious arbiters, specifying refund addresses, and scalability in terms of gas costs. There is potential for improvements, such as earning yield on escrowed assets and supporting contract wallets. The project was led by Alex Kroeger and Kaili Wang from Circle Research, with contributions from the Inflow team.