Startale Group, a Web3 infrastructure firm, has named Sunnyside Labs’ Privacy Boost as the official privacy partner for the Startale App, the consumer-facing platform built on Soneium, the Ethereum Layer 2 network developed by Sony Block Solutions Labs.
The integration will add private transfer capabilities to the app, including the ability to shield assets into private pools, send transfers that hide balances and counterparties, and use privacy-preserving payment flows. The features will be embedded through Privacy Boost’s SDK, with the protocol deploying its full stack natively on Soneium.
This is Privacy Boost’s first integration into a consumer-facing application.
What privacy boost brings to the table
Privacy Boost uses a hybrid architecture that combines zero-knowledge proofs with trusted execution environments (TEEs). The system is designed for sub-500 millisecond proof generation and throughput above 1,800 transactions per second, according to Sunnyside Labs. Users retain custody of their own keys throughout, with no intermediary holding funds.
The protocol also supports what Sunnyside Labs calls “selective auditability.” Transaction details stay hidden from the public, but authorized service operators can access them through an audit view feature for compliance purposes. Sunnyside Labs co-founder and CEO Taem Park told Cointelegraph that selective auditability means transaction details remain hidden from the public, while authorized service operators can review them.
That design has drawn comparisons to existing privacy systems. Zcash, one of the earliest privacy-focused blockchain networks, uses zero-knowledge proofs and supports selective disclosure through viewing keys. However, Privacy Boost’s approach gives operators, not just users, the ability to access shielded records, which changes the trust model.
Sota Watanabe, CEO of Startale Group, said the goal is to give users a choice over when to use privacy rather than making it a default. He framed it as a core feature for what the company is building toward with the Startale App as a “SuperApp.”
Privacy boost already live on OP Mainnet
The Startale integration comes just days after Privacy Boost went live on Optimism’s OP Mainnet on April 21. The product launched as a drop-in SDK enabling confidential computing for Sunnyside’s customers on any OP Stack chain. Soneium, which is also built on the OP Stack, is now the second network where Privacy Boost will be deployed.
On OP Mainnet, the protocol supports confidential token transfers, private smart contract logic, and compliance-compatible architecture with TRM Labs integration for sanctions screening.
Startale’s broader push
The partnership adds another layer to what has been a busy few months for Startale Group.
In March 2026, the company closed a $63 million Series A round led by SBI Group ($50 million) and Sony Innovation Fund ($13 million). The capital is being used to expand its blockchain ecosystem, which now includes Strium (a Layer 1 for tokenized securities), stablecoins JPYSC and USDSC, and the Startale App.
On the stablecoin front, Startale and SBI Holdings are working on JPYSC, a trust bank-backed Japanese yen stablecoin targeting a Q2 2026 launch, pending regulatory approvals. The company also launched Startale USD (USDSC), a dollar-pegged stablecoin built on M0’s platform, as the native digital dollar within the Soneium ecosystem.
Earlier this month, Startale was selected for Hub71’s Digital Assets cohort in Abu Dhabi, one of 27 companies picked from over 2,400 applicants. The move positions the company within Abu Dhabi Global Market as it expands across the Middle East.
What comes next
The Privacy Boost integration is still in development. Startale is planning a phased rollout tied to broader app feature releases.
The scope is expected to expand over time to cover additional payment flows, Mini Apps, and ecosystem integrations within the Startale App. For Soneium, the deployment means developers building on the network will also be able to access Privacy Boost’s tools for their own applications.
Whether the selective auditability model satisfies both privacy advocates and regulators remains to be seen. As blockchain analytics firm TRM Labs noted in a February report, no single privacy approach works for every stakeholder, and hybrid models that balance visibility with access controls may offer the most practical path forward.
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