Blockchain Engineer

About the role

Usether.fi is building a non‑custodial DeFi bank that lets users save, earn, and spend crypto. We are looking for a smart‑contract and backend engineer to design, deploy, and operate our next‑generation yield vaults, the core product that powers one of the largest DeFi yield platforms.

Key responsibilities

• Design, write, test, and deploy Solidity contracts that allocate user capital across DeFi strategies.
• Build and maintain backend services that run 24/7, including redemption solvers, NAV pricing, and liquidity buffers.
• Extend vault architecture to support new assets, chains, and yield strategies.
• Review teammates' code, conduct unit/fuzz testing, invariants, and formal verification where appropriate.
• Collaborate with external auditors and ensure contracts are audit‑ready.
• Participate in daily vault operations: evaluate new protocols, sign transactions, and monitor risk.

Required profile

• Strong experience developing production‑grade Solidity smart contracts.
• Proficiency in building reliable backend systems that operate continuously.
• Deep understanding of DeFi concepts, yield strategies, and risk management.
• Ability to work autonomously in a small, fast‑moving team.

Required skills

• Solidity
• Smart contract development
• Backend development (e.g., Go, Rust, or Python)
• Unit testing, fuzz testing, and formal verification
• DeFi protocols and yield vault architecture
• Ethereum ecosystem

What we offer

• Opportunity to shape a core product in a leading DeFi platform.
• High degree of autonomy and impact.
• On‑site work in NYC, Denver, or the Cayman Islands (4 days/week).