Viva Republica, the operator of South Korea-based mobile money transfer app Toss, has signed a memorandum of understanding with blockchain company Optimism. The partnership will test infrastructure for a Korean won-based stablecoin aimed at institutional payments. The three-month proof of concept will include privacy solutions provider Sunnyside Labs and will use Optimism's OP Stack and Sunnyside's Privacy Boost protocol to assess whether a won-based stablecoin can support domestic blockchain-based payment infrastructure for financial institutions. The pilot comes as stablecoins move further into the payments and settlement debate, with large consumer fintechs examining whether the technology can meet the operational and regulatory requirements expected by financial institutions in major banking markets.
Toss Partners with Optimism and Sunnyside Labs for Won Stablecoin Testing
The project will use Optimism's OP Stack and Sunnyside's Privacy Boost protocol to assess whether a won-based stablecoin can support domestic blockchain-based payment infrastructure for financial institutions. Toss plans to use the proof of concept as the foundation for building compliant stablecoin-based payment infrastructure in South Korea. The company launched in 2015 and says its mobile application has more than 30 million users. Sunnyside is a core developer for the Optimism Collective and has been building core OP Stack infrastructure.
Proof of Concept to Examine Settlement Control and Compliance Integration
The proof of concept will examine whether financial institutions can control the settlement process, whether know-your-customer and anti-money laundering checks can be implemented, and whether transactions can remain private while using a public blockchain ledger. Optimism will provide the blockchain infrastructure through its OP Stack, while Sunnyside Labs will provide privacy-preserving technology designed to shield transfers. The focus on privacy addresses requirements for bank-grade payment infrastructure, where financial institutions cannot expose sensitive transaction details in the same way that many public blockchain applications do.
South Korean Payment Market Explores Local-Currency Stablecoin Infrastructure
South Korea has one of Asia's most advanced digital payments markets, with high mobile banking adoption, active fintech competition, and large domestic payment networks. The project reflects a shift in stablecoin design from dollar-denominated tokens used for crypto trading to local-currency stablecoins that could support settlement, merchant payments, treasury movement, and institution-to-institution transfers. For South Korean regulators, the issue is whether a won-based stablecoin can operate without weakening control over payments, money laundering oversight, or monetary policy transmission.
Payment Firms Test Stablecoin Settlement Across Multiple Blockchain Networks
In April, Shinhan Card partnered with the Solana Foundation to test the commercial feasibility of stablecoin payments and non-custodial wallets after completing an earlier joint pilot project. Shinhan Card has said it hopes to develop DeFi-linked services using blockchain oracles, which connect offchain data with onchain applications. Visa has launched USD Coin settlement services for some U.S.-based financial institutions on Solana, while Mastercard and South Korea's BC Card are exploring stablecoin use cases for payments and settlement.
FAQ
What did Toss announce regarding Korean won stablecoins?
Viva Republica, the operator of Toss, signed a memorandum of understanding with blockchain company Optimism to test infrastructure for a Korean won-based stablecoin aimed at institutional payments. The three-month proof of concept will include privacy solutions provider Sunnyside Labs.
What will the Toss stablecoin proof of concept test?
The proof of concept will examine whether financial institutions can control the settlement process, whether know-your-customer and anti-money laundering checks can be implemented, and whether transactions can remain private while using a public blockchain ledger.
How are other payment firms approaching stablecoin testing?
In April, Shinhan Card partnered with the Solana Foundation to test stablecoin payments and non-custodial wallets. Visa has launched USD Coin settlement services for some U.S.-based financial institutions on Solana, while Mastercard and South Korea's BC Card are exploring stablecoin use cases for payments and settlement.
