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Toss teams with Optimism, Sunnyside Labs on won stablecoin proof of concept

Toss teams with Optimism, Sunnyside Labs on won stablecoin proof of concept

The three-month pilot will test whether Optimism’s layer-2 infrastructure can support a compliant Korean won-pegged stablecoin in South Korea’s tightly regulated payments market.

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Fact Check
The claim is confirmed by multiple independent sources. The Block (via its official X account, TheBlockCo) directly states Toss partners with Optimism and Sunnyside Labs to explore won-denominated stablecoins via an OP Stack proof of concept. Bloomingbit provides detailed corroboration: Viva Republica (Toss's operator) signed an MoU with the two named partners for a three-month PoC on OP Stack infrastructure for a won-pegged stablecoin. BlockBeats independently confirms the same. All core elements of the claim—the three partners, the OP Stack basis, the won stablecoin, and the exploratory PoC nature—are consistently reported.
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Summary

Toss has signed a memorandum of understanding with Optimism and Sunnyside Labs to run a three-month proof of concept for a Korean won-pegged stablecoin. The pilot will test whether Optimism’s OP Stack can meet the throughput, compliance and cost requirements of payment-grade digital currency infrastructure in South Korea, while Sunnyside Labs contributes privacy-focused technology aimed at supporting know-your-customer and anti-money laundering standards. Kyu-ha Kim, Toss’s Chief Business Officer, said the collaboration is intended to assess the feasibility of a won-backed stablecoin. The project adds to Toss’s broader stablecoin push after the company said in March 2026 that it planned to issue a won-backed token, and after Toss Bank signed a separate memorandum of understanding with the Solana Foundation in June to test stablecoin-based remittance and settlement. The Optimism initiative is focused on Ethereum layer-2 infrastructure, while the Solana work targets remittance use cases. No regulatory approvals have been granted and no token issuance details have been disclosed. That leaves the proof of concept as an early technical test in one of Asia’s most tightly regulated financial markets, where a working pilot would still need to clear a potentially longer regulatory path before any launch.

Terms & Concepts
  • stablecoin: A digital token designed to maintain a fixed value relative to a reference asset such as a national currency.
  • OP Stack: Optimism’s modular framework for building blockchain networks that use Ethereum for security and settlement.
  • layer-2: A blockchain scaling system built on top of another network to increase speed or lower costs while relying on the underlying chain.