Rain Protocol Launches SDK v2 to Power Decentralized Prediction Markets on Arbitrum

Rain Protocol has launched SDK v2, a TypeScript toolkit enabling developers and AI agents to deploy custom prediction market platforms on Arbitrum. By integrating on-chain order books and automated market resolution, the update streamlines the infrastructure required for decentralized forecasting, a sector increasingly attracting institutional interest as traditional finance firms explore event-based contracts.

What was announced

SDK v2 represents a significant technical evolution for Rain Protocol, specifically targeting the developer experience through a new TypeScript toolkit. This software development kit is designed to facilitate the creation of custom prediction market platforms, catering to both human developers and the emerging category of AI coding agents that require programmatic access to market creation. A central feature of the upgrade is the introduction of an on-chain order book. This functions alongside Rain’s existing automated market maker (AMM) model, providing a hybrid approach that allows platform creators to choose or combine liquidity strategies based on their specific market needs and asset volatility.

Furthermore, SDK v2 transitions critical governance and operational functions—including market resolution, disputes, and appeals—directly into the protocol on-chain. This shift is intended to remove centralized points of failure in the settlement of prediction outcomes, ensuring that the entire lifecycle of a market is transparent and verifiable. To improve the end-user experience, the SDK introduces real-time market updates and significantly reduces the number of transaction approvals required for traders to execute positions. These technical refinements aim to make on-chain trading feel as responsive as centralized alternatives while maintaining the security of the Arbitrum network.

The companies involved

Rain Protocol is a developer of decentralized infrastructure for forecasting and event-based markets, focusing on creating modular tools for the DeFi ecosystem. Its choice of Arbitrum as a foundation is strategic; Arbitrum is a leading Layer 2 scaling solution for Ethereum, developed to handle high transaction volumes with significantly lower fees than the Ethereum mainnet. It has established itself as a primary destination for DeFi protocols that require high-frequency interactions, such as trading and real-time data updates. The announcement also highlights the growing intersection between crypto-native protocols and traditional finance by referencing Kalshi and Cantor Fitzgerald. Kalshi is a regulated exchange dedicated to event contracts, allowing users to trade on the outcome of real-world events. Its recent partnership with Cantor Fitzgerald, a major global financial services firm known for its presence in institutional brokerage and investment banking, brings Kalshi’s products to a sophisticated client base of hedge funds and family offices. This institutional validation of prediction markets provides a backdrop for Rain Protocol’s efforts to decentralize the underlying technology used to build such platforms.

What FF News has reported before

FF News has closely tracked the expansion of capital markets on the Arbitrum network. Recently, we covered how Anchored to Launch Tokenized Stocks on Arbitrum via UniswapX for Onchain Capital Markets, highlighting the chain's role in institutional asset migration. The trend of bringing traditional financial instruments on-chain was further evidenced when Dinari Launches First Tokenized U.S. Stocks for Self-Custody Trading via USDC Partnership. Additionally, the integration of blockchain with real-world spending was noted in our report on how Tria Integrates Robinhood Chain to Enable Real-World Asset Spending via Tria Card. We also reported on liquidity infrastructure improvements in EDGE Markets Partners with ProphetX to Enable $1M Daily Real-Time Deposits for Traders, which mirrors the push for real-time updates seen in Rain Protocol’s latest SDK.

What this means

The launch of SDK v2 signals a move toward "invisible" infrastructure in decentralized finance. By reducing transaction approvals and moving resolution on-chain, Rain Protocol is addressing the friction that has historically kept prediction markets niche. The market for event-based trading is currently under significant pressure to prove its utility beyond speculative cycles, and the involvement of institutional heavyweights like Cantor Fitzgerald suggests that the "oracle problem" is being solved through more robust protocol design. As AI agents begin to participate in these markets, the speed and automation enabled by this SDK could force traditional forecasting firms to accelerate their own digital transformations or risk losing liquidity to more agile, on-chain alternatives.