Toss, the operator behind South Korea’s leading mobile payment platform with over 30 million users, has teamed up with Optimism and Sunnyside Labs to launch a three-month proof of concept for a Korean won-backed stablecoin designed for institutional payments. Announced on July 8, 2026, the partnership will test the viability of a compliant, privacy-preserving digital won using Optimism’s OP Stack as the blockchain infrastructure and Sunnyside Labs’ Privacy Boost protocol to shield transaction details while maintaining transparency on a public ledger.
The PoC focuses on evaluating whether a won-based stablecoin can operate within domestic settlement systems while meeting strict KYC and AML requirements. Toss, through its parent company Viva Republica, aims to explore how financial institutions could control settlement flows, enforce compliance, and protect privacy—critical steps toward building stablecoin-enabled payment rails that satisfy South Korean regulators.
This move places Toss among a growing list of financial players embracing stablecoins. In late April, Shinhan Card partnered with the Solana Foundation to test stablecoin payments and non-custodial wallets, while Visa recently rolled out USDC settlement services on Solana for select US institutions. Mastercard and BC Card are also exploring similar innovations. Toss’s collaboration with Optimism and Sunnyside Labs signals a strategic push to align with global stablecoin trends while tailoring infrastructure to the Korean won settlement ecosystem.
