StarkWare has opened OffMarket to the public after a limited early release that initially began in August, offering a way to trade on Polymarket without publicly tying every position to a user's main account. The Block reported the public rollout on October 14, while OffMarket's live site explains that the service uses the same Polymarket markets, order book and odds. OffMarket is not a Polymarket product or affiliate, and the service applies the prediction platform's geographic restrictions.

Fresh wallets separate positions from a main account

OffMarket routes funds through Starknet's shared privacy pool and creates a fresh Polygon wallet for each position. According to the service, the trading wallet is derived from the user's signature and places orders on Polymarket, where the position remains in Polymarket's smart contracts. The fresh wallet has no direct onchain connection to the user's main wallet or other positions. The interface is non-custodial: users sign meaningful actions in their browser, and the service says private keys are not transmitted to an OffMarket server.

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Zero-knowledge proofs protect the pool's private state

The underlying Starknet privacy protocol uses encrypted notes and zero-knowledge proofs. Its open-source documentation says users submit private actions through an SDK, a proving service returns validity proofs, and Starknet verifies those proofs before updating the pool contract. OffMarket says USDC moves between Starknet and Polygon through Circle's Cross-Chain Transfer Protocol. The Block reported that deposits are currently capped at $1,000 USDC per account. The developer has not published user counts or trading volume for the limited release.

Privacy does not make the trade invisible

OffMarket reduces the public link between a person and a prediction-market position; it does not hide the existence of the trade. An observer can still see USDC leaving the shared pool for a Polygon address, that address trading on Polymarket, and the resulting position and profit or loss. The Block reported that transaction size and timing could still help an observer infer a connection, particularly when few users move similar amounts at the same time. The service therefore offers unlinkability rather than complete anonymity.

Compliance access is built into the design

The service also preserves a path for legally required disclosure. OffMarket says an auditing entity holds a viewing key in escrow for compliance tracing. The Block identified that entity as Financial Privacy Inc. and reported that the key is kept inside a secure enclave. StarkWare said deposits are screened against sanctions lists and that approved legal requests can reveal only the information covered by the request. The viewing arrangement does not give the auditor control of user funds, according to the company.

A public launch with operational limits

OffMarket participates in Polymarket's verified builder program but has no formal partnership or special market access, according to The Block. Orders execute against the same buyers, sellers and prices as regular Polymarket trades, while private orders take about a minute and withdrawals take several minutes. Polymarket can disable the builder code, and existing regional restrictions remain in force, including the block on U.S. users. The launch provides a working application for Starknet's privacy stack, but its deposit cap, limited disclosure data and residual timing risks leave adoption and privacy performance to be tested at larger scale.

Sources

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