StarkWare opens OffMarket for more private Polymarket trading

StarkWare opened OffMarket to the public on Oct. 14, letting Polymarket users trade without publicly tying their positions to their existing accounts. The service uses Starknet’s shared privacy pool to obscure the path between a user’s deposit and a fresh trading wallet. The Block’s report on OffMarket says the service had been in limited release since August and currently caps deposits at $1,000 USDC per account.

How does OffMarket route a trade?

A user deposits funds into Starknet’s open-source privacy pool, then uses OffMarket to trade through a wallet derived from the user’s signature. The pool mixes deposits, making it harder to connect the fresh wallet to the original account. It works like a shared queue: the more deposits passing through it, the harder it can be to identify which one funded a given wallet. StarkWare says the service is non-custodial, with users keeping control of their keys in their browsers.

The order still goes to Polymarket. It executes against the same buyers and sellers and at the same market prices as a regular order. OffMarket does not create separate markets or change how Polymarket settles positions. Users can recover their wallets using their signatures if OffMarket goes offline, according to StarkWare’s spokesperson.

What remains visible on-chain?

The privacy layer hides the link to the original depositor; it does not make trading activity invisible. Polymarket trades, prices and positions remain public on Polygon, and USDC transfers from the shared pool to a fresh wallet can be seen. The Block reported that transaction size or timing could still help identify a trader. A smaller pool of active users could also make it easier to infer who made a deposit.

Starknet’s shared pool had about $1.5 million across 17,000 deposits, according to L2BEAT figures cited by StarkWare. StarkWare did not provide user numbers or trading volumes for OffMarket’s limited release. The service’s $1,000 deposit cap may change depending on demand and usage, the spokesperson told The Block.

Who can use it, and what oversight applies?

OffMarket is not a Polymarket product and has no formal partnership or special access to the platform. It is part of Polymarket’s verified builder program, but Polymarket can disable its builder code. The service also applies Polymarket’s geographic restrictions, including the ban on U.S. users.

StarkWare says the service screens deposits against sanctions lists. Financial Privacy Inc. holds the master viewing key in a secure enclave and reviews requests for transaction information from authorities. The key does not give the firm access to users’ funds, and StarkWare and the firm secure it through a multisignature arrangement.

Sources

• The Block’s report on OffMarket — theblock.co