AI Tools and Whitechain Mainnet Dominate ETHGlobal Mumbai Hackathon

ETHGlobal Mumbai, the last in-person hackathon of 2026, opened with 1,600 attendees, 32% of whom were new to Web3 13. During the opening ceremonies, Kartik Talwar noted the event's focus on builders and live demos 13. Whitechain, an EVM Layer-2 built with OP Stack, announced its mainnet went live the previous week 714. The chain offers four prize tracks totaling $15,000 and encourages AI-assisted development 714.

AI-powered development tools were a central theme across workshops. Hedera demonstrated a skill plugin for Claude Code that teaches the agent how to build on Hedera 5, while the Hedera Harness tool was introduced to provide verifiable, agent-generated code by separating the generation and evaluation steps 15. Arc Studio, a coding agent harness from Circle, was presented as a way to marry on-chain and off-chain development lifecycles 2. Definitive Flash offered an API for advanced order types, emphasizing agent-first design 16.

The Ethereum Stablecoin Summit, held alongside the hackathon, covered the evolution of stablecoins. Kevin Li argued that stablecoin supply is flattening because stablecoins are becoming the settlement leg for faster-moving capital 9. Navin Vethanayagam made the case for a Korean won stablecoin, noting that "the Korean won is already the second most traded fiat currency in all of crypto" 12. Eleni Steinman of Lead Bank described how banks can integrate stablecoins by providing programmable interfaces for compliance and settlement 10. Nitya Subramanian stressed that stablecoin payments need rules, not just rails, and introduced a programmable policy engine for compliance 11.

Other notable tools presented included the Uniswap stack with hooks for customizable AMMs 6, Chainlink’s CCIP 2.0 for cross-chain value transfer 18, Arkiv as a Web3 database with structured data indexing 3, and ENSv2 for identity management and subdomains 8. 1inch Aqua was pitched as a shared liquidity layer that keeps funds in the liquidity provider’s wallet 4.

A fireside chat between Vitalik Buterin and Kartik Talwar touched on the growing intersection of AI and Ethereum. Buterin observed that the community is now focused on solving problems rather than making tools the end goal 1. The hackathon ran for 36 hours, with participants building projects across multiple chains and submitting live demos 17.

• Talks worth watching: 1 Vitalik Buterin and Kartik Talwar on Ethereum as a store of value; 2 Arc Studio for on-chain coding agents; 5 Hedera X Claude Code – AI skills for builders; 7 Whitechain tracks and tips; 9 Money that moves itself – stablecoins as settlement; 12 Korean won stablecoin opportunity; 15 Hedera Harness for verifiable AI code; 18 CCIP 2.0 for cross-chain applications.