Sourdough

I joined S16 Research Ventures to work on exactly this problem. Web3 treasury management was a mess — teams were juggling multiple wallets across chains, signing transactions one at a time, and doing it all in public. Any competitor could watch your treasury on-chain in real time: your balances, your payment counterparties, your timing patterns. That's not acceptable for a real business, and no existing tool was addressing it.

Sourdough is built on a Cosmos SDK chain with CosmWasm smart contracts handling multisig logic and team policy enforcement. Cross-chain execution flows through an MPC relayer that signs transactions on EVM and Solana without exposing individual private keys — no single point of compromise. Privacy on EVM is provided by Railgun integration, which shields balances and transaction flows from public chain analysis. Private keys are protected by a combination of TEE and MPC. The whole thing is non-custodial: Sourdough never holds funds, and users can export their keys and recover independently if the service ever disappears.

The hardest engineering problem was making a multichain product feel like a single product. Cosmos, EVM, and Solana have different signing formats, different fee models, different confirmation times, and different notions of what "a transaction" even is. Designing a policy layer — team permissions, approval thresholds, multi-sig rules — that syncs consistently across all three chains without requiring users to understand which chain they're on was the core challenge. The abstraction had to be real, not cosmetic.

Sourdough shipped to mainnet covering 7+ chains. Teams use it to run payroll, pay expenses, and receive payments without exposing treasury balances to the public blockchain. A single signature executes transfers across chains simultaneously. Approval rules set once apply everywhere. The privacy layer means payment flows are visible only to authorized signers. It's the most operationally complex project I've shipped.