StarkWare has officially rolled out OffMarket, a new privacy service designed to empower users on the prediction market platform Polymarket with enhanced trading anonymity. The service, which leverages zero-knowledge technology on Starknet, aims to obscure user trading positions from public scrutiny. This move directly addresses mounting concerns over the transparency inherent in public blockchain records.
The new offering began its limited early release in August 2026, following a phased rollout that included a private alpha in July and invite-only access. Now publicly available around mid-October 2026, OffMarket enables users to trade without linking their positions directly to their main accounts. This functionality is crucial for traders seeking to maintain discretion in a market where every transaction is typically visible.
How StarkWare OffMarket enhances privacy on prediction markets
Polymarket, like many decentralized platforms, records all trades publicly on the Polygon network. This transparency means that anyone can examine an account’s positions, order sizes, and complete trading histories. While this public ledger offers auditability, it also exposes users to potential doxxing and scrutiny.
The need for greater privacy became glaringly apparent in 2024 when blockchain analysts linked several accounts to a French trader who had wagered tens of millions of dollars on Donald Trump winning the U.S. presidential election. More recently, Bloomberg reported identifying at least 34,000 trades flagged as possible insider activity between August 2025 and June 2026. These incidents underscore the transparency challenge facing prediction markets.
The Public Nature of On-Chain Trading
The inherent openness of blockchain transactions has always been a double-edged sword. It champions decentralization and auditability, but simultaneously strips away the financial privacy many expect in traditional markets. For high-stakes prediction markets like Polymarket, this visibility can attract unwanted attention and even enable sophisticated forms of front-running or market manipulation.
OffMarket endeavors to create a more private trading environment without compromising the integrity of the market. It allows participants to engage in often sensitive political or economic predictions without their entire portfolio becoming a public record. This is a significant step towards bringing a degree of conventional market privacy to the decentralized prediction space.
Regulator Scrutiny and Market Evolution
Polymarket itself has navigated a complex regulatory landscape, especially in the United States. It faced a $1.4 million fine from the Commodity Futures Trading Commission (CFTC) in January 2022 for operating as an unregistered derivatives exchange. Following a period of blocking U.S. customers, Polymarket re-entered the U.S. market in December 2025 after acquiring a CFTC-licensed derivatives exchange and receiving a “no-action” letter.
This history highlights the delicate balance between innovation and regulation in decentralized finance. Tools like OffMarket could play a role in how prediction markets evolve, potentially offering a more palatable framework for both users and regulators concerned about financial stability concerns and market integrity, though the service adheres to Polymarket’s existing geographic restrictions, including the U.S. ban on its main platform.
OffMarket’s Technical Underpinnings
At its core, OffMarket operates using zero-knowledge technology, a cryptographic method that allows one party to prove the validity of a statement to another without revealing any additional information. This is executed on Starknet, an Ethereum Layer 2 network developed by StarkWare.
Users begin by depositing USDC onto the platform, currently capped at $1,000 per account. These funds then sit within Starknet’s open-source privacy pool. From there, OffMarket manages derived wallets on behalf of users, effectively separating their trades from their primary on-chain identities. Orders are executed against Polymarket’s existing order books, ensuring market prices remain consistent for both private and public traders.
Zero-Knowledge Technology at Play
Zero-knowledge proofs, or ZKPs, are a cornerstone of modern blockchain privacy.
StarkWare co-founder and CEO Eli Ben-Sasson, a founding scientist of Zcash, articulated his longstanding commitment to financial privacy, stating, “Zcash, which is huge today, was born out of conviction by me and others that privacy matters and people would come to value it — even if it took years.”
He believes this conviction now drives the integration of zero-knowledge technology into Polymarket through OffMarket.
The non-custodial nature of OffMarket is another key technical detail. Users retain full control of their private keys within their browsers. This means that even if OffMarket were to go offline, users could recover their wallets using their original signatures.
The privacy pool contract underwent an audit by OpenZeppelin in June 2026, with no critical or high-severity issues reported, and was formally verified by StarkWare in July 2026, reinforcing its security claims.
Navigating Operational Limitations
Despite these privacy enhancements, a StarkWare spokesperson acknowledged that OffMarket cannot completely anonymize a trader. Transaction sizes or the precise timing of trades could still potentially allow for inference of a trader’s identity. The underlying markets, prices, and trades remain public on Polymarket itself.
Furthermore, while the service masks the original depositor, USDC transfers from the shared privacy pool to a fresh wallet are visible, as are any subsequent Polymarket trades from that address.
The spokesperson noted that if fewer individuals were using the shared pool, currently holding approximately $1.5 million across 17,000 deposits, it might become easier to trace transactions. StarkWare has indicated plans to adjust the initial $1,000 USDC deposit limit based on demand.
StarkWare’s Broader Privacy Strategy
OffMarket isn’t an isolated development; it fits into StarkWare’s broader strategic push for enhanced privacy across the Starknet ecosystem. The company has been at the forefront of implementing zero-knowledge proofs not just for scalability, but also for user privacy.
In June 2026, Starknet rolled out its STRK20 privacy framework. This innovation allows ERC20 token balances and transfers to be shielded, offering a layer of confidentiality for digital assets. Crucially, it includes provisions for retaining viewing keys for legally required disclosures, balancing privacy with regulatory compliance. This framework represents a significant step beyond simple mixers, embedding privacy directly into the asset layer.
Expanding the Starknet Privacy Ecosystem
Just a day before OffMarket’s public launch, on October 13, 2026, StarkWare introduced another STRK20 feature: Shadow Accounts. These allow users to engage with individual applications without publicly linking their activity to their main wallets. Users can fund these accounts from their shielded STRK20 balances, creating a more discreet interaction layer for various decentralized applications.
These initiatives, including OffMarket, underscore StarkWare’s commitment to building a comprehensive privacy infrastructure. The firm recognizes that as the broader cryptocurrency market matures, user demand for confidentiality will only grow. This proactive development of privacy layers helps position Starknet as a leading network for users who value both transparency and discretion in their on-chain activities.
Compliance and the Future of Private Trading
OffMarket operates independently of Polymarket, without any formal partnership or special access, although it is part of Polymarket’s verified builder program. A StarkWare spokesperson confirmed that while Polymarket was aware of the project and “happy” with it, there were no specific discussions about its launch. Polymarket retains the ability to disable builder code if necessary.
Compliance is a critical aspect, especially for privacy-enhancing tools in finance. Independent compliance firm Financial Privacy Inc. (FPI) plays a pivotal role here. FPI maintains a master viewing key within a secure enclave, using it to screen deposits against sanctions lists. Their counsel reviews requests for transaction information from courts, regulators, and agencies.
Oversight and Legal Frameworks
FPI’s involvement highlights the delicate balance between privacy and regulatory obligations. The firm has the authority to refuse requests for information if it cannot verify their legal basis, authenticate them, or confirm the requesting authority has the necessary powers. When approved, FPI only releases information strictly covered by the request.
It’s important to note that this viewing key does not grant FPI access to users’ funds, which remain non-custodial. StarkWare and FPI jointly secure this key through a multisignature arrangement.
The introduction of OffMarket signals a new era for prediction markets, where the benefits of blockchain transparency are tempered by user demand for privacy. As decentralized finance continues to evolve, the development of robust, compliant privacy solutions like OffMarket will likely become increasingly common, shaping how individuals interact with on-chain applications while adhering to necessary legal and ethical standards.