Toss Tests Won Stablecoin on Optimism's OP Stack

Toss, a South Korean fintech giant, is joining forces with Optimism and Sunnyside Labs to test a won-based stablecoin on the OP Stack. The three-month proof of concept will examine whether blockchain payment rails can meet institutional standards for settlement control, compliance, and privacy in South Korea.

Toss has built one of Asia's largest fintech user bases, with over 30 million users across its financial super app. A working won-stablecoin rail would give the company a path to test blockchain settlement inside a payments network that already touches banking, transfers, brokerage, lending, and merchant services.

The OP Stack provides Toss with a modular execution framework, while Sunnyside Labs' Privacy Boost is designed to shield sensitive payment data on public blockchain infrastructure. This setup targets one of the biggest gaps between consumer crypto rails and bank-grade financial systems: payments must settle quickly, but customer information and transaction details cannot be fully exposed to the public network.