Spark is building one of the most important pieces of infrastructure in DeFi: a scalable on-chain capital allocation engine designed to move billions in liquidity efficiently across lending markets, yield strategies, and liquidity venues. As the ecosystem matures, the challenge is no longer simply creating protocols, but designing systems that can intelligently deploy capital, generate sustainable yield, and manage liquidity at scale across increasingly fragmented markets. Spark sits directly at the center of that evolution. We are looking for a Senior Smart Contract Engineer to help architect and build the core primitives behind Spark’s vault infrastructure, AMM integrations, and yield-generating systems. This is a deeply technical role focused on designing secure, capital-efficient smart contract systems that interact with lending protocols, liquidity pools, and automated strategy frameworks across the DeFi ecosystem. The ideal candidate understands that modern DeFi infrastructure is ultimately a liquidity coordination problem. You should be comfortable thinking about how capital moves between protocols, how yield is generated and distributed, how vault systems abstract complexity for users, and how liquidity mechanisms behave under real market conditions. You will work on: • ERC-4626 vault architectures • Yield allocation and rebalancing systems • AMM and liquidity pool integrations • Automated capital deployment frameworks • Treasury and liquidity management infrastructure • Reward distribution and fee accounting systems • Strategy execution and risk-aware routing mechanisms A large part of the role involves building systems that abstract complexity while remaining transparent, composable, and secure. You will contribute to infrastructure responsible for managing large-scale on-chain liquidity and enabling efficient access to yield across the broader DeFi landscape. This is not a role focused purely on writing Solidity in isolation. We are looking for someone who understands the economic behavior behind the code: • how liquidity behaves under volatility, • how yield incentives shape user behavior, • how AMMs impact capital efficiency, • how vault architectures can optimize deployment strategies, • and how protocol design decisions influence systemic risk. You’ll collaborate closely with protocol engineers, treasury and risk contributors, and product stakeholders to design systems that can scale responsibly while remaining highly composable within the broader Ethereum ecosystem. What We’re Looking For You likely have several years of experience building production-grade smart contracts and have worked on systems involving: • vaults, • lending markets, • AMMs, • liquidity routing, • staking or yield systems, • or broader DeFi infrastructure. You should feel comfortable owning systems end-to-end, from architecture discussions and protocol design to implementation, testing, optimization, and audit preparation. Strong candidates will typically have experience with: • Solidity • Foundry / Hardhat • ERC-4626 vault standards • AMM mechanics and LP accounting • Yield aggregation systems • Oracle integrations • Upgradeable contract architectures • Gas optimization and security best practices Experience working on live protocols with meaningful TVL is highly valuable, particularly if you have operated systems exposed to real liquidity conditions and adversarial environments. We are especially interested in engineers who naturally think in terms of: • capital efficiency, • liquidity flows, • incentive alignment, • composability, • and protocol-level risk. What Success Looks Like In this role, success means designing systems that are: • secure under stress, • efficient in capital deployment, • easy to integrate with, • economically sustainable, • and capable of scaling across an increasingly modular DeFi ecosystem. You will help shape infrastructure that sits underneath lending markets, savings products, liquidity strategies, and yield-generating primitives used across the broader on-chain economy.