Circle Introduces Simplified Onchain Payments with Permit2 Integration

Circle has announced a significant enhancement to its Circle Payment Network (CPN) by integrating Uniswap’s Permit2 standard. This move aims to streamline and secure onchain payment settlements, according to circle.com. The new payment flow, part of the Onchain Transaction V2, introduces an authorization framework that simplifies the payment experience for developers working with stablecoins such as USDC and EURC.

A Simpler Onchain Payment Experience

With the release of Onchain Transaction V2, CPN now offers an optional upgrade that abstracts blockchain processing fees and streamlines transaction signatures. Users can pay blockchain fees in USDC, eliminating the need to manage native tokens. Transactions leverage EIP-712 typed data for signing, removing the need for raw transaction management. Additionally, CPN can automatically broadcast and expedite transactions, ensuring timely settlements.

The CPN PaymentSettlement Contract, a new smart contract, plays a crucial role in this process by verifying and executing transactions. This contract enforces time and nonce rules and settles payments by using Permit2 to pull funds from the payer before distributing them to the payee and beneficiaries.

Transition from ERC-3009 to Permit2

Circle’s decision to move from ERC-3009 to Permit2 is a strategic shift towards a more flexible and stablecoin-agnostic approach. While ERC-3009 required each token to implement its own transferWithAuthorization method, causing fragmentation, Permit2 abstracts token approvals into a shared contract. This change enhances interoperability and simplifies the developer experience across the ERC-20 ecosystem.

How Permit2 Enhances CPN Payment Flow

Permit2, developed by Uniswap Labs, is central to the new CPN payment flow. It manages the authorization layer, while the PaymentSettlement Contract handles transaction verification. The Relayer Service facilitates relaying and blockchain processing fees. This setup ensures that the payment process is efficient and secure.

The process involves two levels of approval: a master approval where the Originating Financial Institution (OFI) grants Permit2 an ERC-20 allowance, and a sub-approval for each payment, designating the PaymentSettlement Contract as the spender. This structure ensures that funds are securely managed and transactions are executed as intended.

Benefits for Developers

Developers can benefit from using Permit2 by enabling signature-based ERC-20 approvals, allowing for offchain authorization. This design simplifies nonce tracking and blockchain fee management, as transaction validation and broadcasting are handled by the Relayer.

Circle’s Wallets API supports programmatic approval of Permit2, allowing developers to automate and streamline their payment processes. The updated CPN V2 API endpoints facilitate the creation of payment quotes and transaction execution, enhancing the overall developer experience.

Conclusion

The integration of Permit2 with Circle’s PaymentSettlement Contract is a significant step towards simplifying onchain settlements. By enabling signature-based approvals and automating transaction management, Circle is providing a faster, more secure, and efficient payment solution for developers working with stablecoins.

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