StarkWare has publicly launched OffMarket, a privacy service that allows Polymarket users to trade without publicly linking their positions to their main wallets. The service, built on Starknet, uses zero-knowledge technology and a shared privacy pool to separate deposited funds from the wallets that execute trades on Polymarket. It had been available in a limited release since August.
OffMarket is non-custodial: users retain control of their keys in their browsers. User funds sit in Starknet's open-source privacy pool, while Polymarket positions are held in its contracts under wallets derived from users' signatures. A spokesperson said wallets can be recovered using those signatures if OffMarket ever goes offline. Deposits are currently capped at $1,000 USDC per account, with StarkWare planning to adjust the limit according to demand and usage. OpenZeppelin audited the pool contract in June and reported no critical or high-severity findings, and StarkWare formally verified the contract in July.
Orders are executed on Polymarket's existing order books against the same buyers and sellers at the same market prices. StarkWare said private orders take about one minute to execute, while withdrawals take a few minutes. Polymarket's normal taker fee applies, with minimal additional network costs. However, the privacy layer does not hide everything: trades remain visible on Polygon, including size, timing, and associated wallet addresses. Observers may still identify traders through transaction size or timing, and fewer users in the shared pool could make analysis easier.
OffMarket is not a Polymarket product and has no formal partnership with the platform, though it belongs to Polymarket's verified builder program. It follows Polymarket's geographic restrictions, including the ban on U.S. users. Compliance firm Financial Privacy Inc. holds the master viewing key in a secure enclave, screens deposits against sanctions lists, and reviews requests for transaction information from courts, regulators, and agencies. StarkWare co-founder and CEO Eli Ben-Sasson said the project grew out of his longstanding work on financial privacy, citing Zcash as an earlier conviction that people would come to value privacy.
