Blockchain Engineer - ether.fi

About us

ether.fi is a fast-growing crypto-native financial platform on a mission to put users in control of their wealth, making it easy to save, earn, and spend crypto. As a leading decentralized finance (DeFi) bank, ether.fi offers a fully integrated, non-custodial suite of products (Stake, Liquid, and Cash) that bridge crypto utility with real-world convenience.

Nonce is the team behind ether.fi's DeFi yield vaults, the products that take user deposits and put them to work across DeFi. A depositor gets a single position and a yield-bearing token. Behind it sits a mandate, a set of whitelisted protocols and strategies, live NAV accounting, and a redemption path that has to stay honest whether the market is calm or not. The whole job is deploying into lending markets, LSTs and LRTs, basis and funding trades, stablecoin strategies, and whatever comes next, safely, with the risk understood before the capital moves.

It's a small team with a lot of autonomy. Every vault, every rebalance, and every new protocol integration goes through this team.

Learn more at ether.fi.

Position overview

We're hiring a smart contract / backend engineer to help build and operate ether.fi's DeFi yield vaults. You'll write the contracts that allocate user capital, build the tooling/systems that runs 365/24/7 to safely monitor and manage the capital.

The immediate focus is the next generation of Nonce's vault product to power one of the largest DeFi yield vaults products in the industry. Getting that right, and keeping it secure, is the main thing this role is here to do.

This is a build-and-operate role. You'll ship Solidity and backend services, and you'll also share the day-to-day of running live vaults: discussing new yield opportunities, reviewing transactions, signing them, and deciding whether a new protocol is safe to allocate into. The team is small, so the people who write the vaults are the people who run them.

This role is onsite 4 days per week at one of our global offices: NYC, Denver, or the Cayman Islands.

What you'll work on

Vaults

• Design, write, deploy, and configure yield vault smart contracts alongside the rest of the vault team
• Build vault tooling: putting on trades, rebalancing across strategies, updating vault policies and whitelists, admin configuration
• Extend the vault architecture as new yield strategies, assets, and chains come online
• Review teammates' contracts and tooling, and get reviewed in turn
• Prove the contracts do what they claim: unit and fuzz tests, invariants, and formal verification where it earns its keep
• Work with external auditors through review cycles, and write contracts that are straightforward to audit in the first place

Backend services

• Build and maintain the critical systems that run 365/24/7 without failure: the solver powering redemption flows, including the liquidity buffer, report NAV changes, security concerns and unwind logic behind them
• Build and maintain the NAV service, pricing every position a vault holds, and the accuracy guarantees behind the share price
• Automate on-chain operations so allocation, harvesting, and rebalancing run reliably without a human in the loop

Risk and protocol operations

• Own the new-protocol review pipeline: given a new protocol, read the docs and contracts, assess the risk, and decide whether and on what terms we allocate
• Review and sign vault rebalancing transactions as a multisig signer
• Build monitoring and automation that catches a broken oracle, a depeg, a stuck withdrawal, or a bad allocation before users do
• Participate as a security guardian across ether.fi's web3 stack and operations

You might be a fit if you

• Write strong production Solidity: clean, secure, and designed around edge cases and failure modes
• Are equally strong on the backend: services, automation, and tooling that hold up when they're running against real money
• Know DeFi deeply enough to read a protocol's docs and contracts, understand where the yield actually comes from, and form your own view on where it breaks
• Have 4+ years of industry engineering experience
• Have shipped a real yield vault (ERC-4626, BoringVault-style, or your own architecture) and operated it after launch
• Thrive in fast-moving environments where the best idea wins

Bonus

• Experience at a vault platform, asset curator, or yield product with real TVL, either building the vaults or curating what goes into them
• Hands-on with the strategies themselves: lending markets, LSTs and LRTs, basis and funding trades, stablecoin yield
• Audit or security review background
• You've hacked on this for fun: your own contracts, protocol audits, MEV bots, or just a lot of hours across DeFi protocols