Updated Jul 8, 2026
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Toss, Optimism and Sunnyside Labs to test Korean won stablecoin in payments proof of concept

SEOUL, July 8. South Korean mobile payments application Toss has reportedly agreed with the Optimism ($OP) blockchain network and Sunnyside Labs to run a proof of concept on whether a Korean won-denominated stablecoin is viable for payment use. The arrangement, described in a published report, has not been confirmed by any of the three parties in an official statement.

By Yuki Tanaka2 min read$OP
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SEOUL, July 8. South Korean mobile payments application Toss has reportedly agreed with the Optimism ($OP) blockchain network and Sunnyside Labs to run a proof of concept on whether a Korean won-denominated stablecoin is viable for payment use. The arrangement, described in a published report, has not been confirmed by any of the three parties in an official statement.

Three-party arrangement

The proof of concept names three participants. Toss is the mobile application on the payments side. Optimism, whose native token is $OP, is the blockchain on which the stablecoin would be developed. Sunnyside Labs is named as the third party, though the report does not describe what Sunnyside Labs contributes or which organization is directing the work. The report does not cite a company filing, press release, or regulatory disclosure from any of the three.

What the feasibility study covers

The POC targets the Korean won as the stablecoin's peg, with payments as the stated use case. A feasibility study at this stage tests whether a design can work before any token is issued. The source does not detail the stablecoin's proposed issuance mechanism, the technical infrastructure to be deployed on the Optimism network, which payment categories are in scope, or what success criteria the parties have agreed on. No timeline was given. No funding amount was disclosed. Whether South Korean financial regulators are engaged in the effort was not addressed in the source.

Limits of the reporting

The source is a media report. None of Toss, Optimism, or Sunnyside Labs had publicly confirmed the arrangement as of publication. The report identifies the partners and the subject of the POC. The terms of the collaboration and the mechanics of any token that might result were not disclosed.

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Key takeaways

Frequently asked

Who are the parties involved in the proof of concept?

The three named participants are Toss, the mobile payments app; Optimism, the blockchain network whose native token is $OP; and Sunnyside Labs, whose specific contribution is not described in the report.

What currency would the stablecoin be pegged to?

The stablecoin would be pegged to the Korean won, with payments as the stated use case.

Has the arrangement been officially confirmed?

No; the arrangement comes from a media report and none of Toss, Optimism, or Sunnyside Labs had publicly confirmed it as of publication.

Has a token been issued yet?

No; the effort is a feasibility study that tests whether the design can work before any token is issued, and the proposed issuance mechanism was not detailed.

Were a timeline or funding details disclosed?

No timeline was given and no funding amount was disclosed, and the success criteria for the proof of concept were not detailed.