Senior Protocol Engineer

Project Eleven is an applied lab of builders and technologists working at the intersection of quantum computing and cryptography. We build impactful solutions that push the digital-asset ecosystem to a more secure future. Our focus is post-quantum migration: upgrading wallets, identity, and settlement rails to quantum-safe primitives without breaking UX, composability, and developer workflows.

Our mission is to future-proof digital assets and preserve self-sovereignty in a post-quantum world. We do that by building the canonical tooling and products teams can adopt: crypto-agile infrastructure, reference implementations, and integrations that fit real constraints like latency, cost, compatibility, key rotation, and recovery.

We work with leading ecosystems to make this migration real through products we build, audits, testnets, and cutting edge research. The vision we are have is clear: a proven upgrade path, production-ready tooling and users retaining control of their assets and identity, before CRQC exists.

We're looking for a Senior Protocol Engineer to join our growing Product Engineering team. As a Protocol Engineer, you'll play a pivotal role in helping to build the canonical tools and products to protect digital assets and preserve self-sovereignty in a post-quantum world.

This role is a full-time, fully remote position in Europe (GMT to GMT+2).

• Design, implement, and maintain long-lived smart contracts intended for production use and high-value deployments

• Own contract architecture decisions including upgradeability, storage layout, initialization, and lifecycle management

• Identify, mitigate, and document security risks related to smart contracts and on-chain protocol logic

• Prepare contracts for external audits, respond to findings, and implement remediation safely

• Develop comprehensive test suites including unit tests, integration tests, fork testing, and fuzzing

• Manage contract deployments, upgrades, and post-deployment monitoring in live environments

• Collaborate with off-chain engineers to ensure safe and consistent interaction between on-chain and off-chain systems

• Evaluate and adopt relevant standards and best practices within the smart contract ecosystem

• Deep experience with Solidity development and shipping production contracts

• Strong understanding of proxy patterns, upgrade safety, storage, initialiser patterns, contract lifecycle management

• Excellent knowledge of EVM internals and common vulnerabilities e.g. Reentrancy, storage collisions, signature replays etc

• Demonstrable experience preparing contracts for formal audits

• Familiarity with ERC standards (especially ERC-20, ERC-721, ERC-4337, ERC-1271)

• Experience deploying and maintaining high-value contracts on mainnet e.g. deployments, proxy upgrades with no downtime, post-deployment monitoring

• Strong testing and debugging e.g. complex integration tests, gas profiling and optimisations, fork testing, fuzzing

• Strong English communication

• Experience with ERC-4337 account abstraction

• Awareness and understanding of post-quantum cryptography

• Experience developing with ZeroDev, Biconomy or Alchemy accounts

• Token Sale / ICO experience i.e. an understanding of vesting schedules, token distribution contracts, TGE mechanics

• Auditor collaboration - Experience working with auditors and running internal pre-audits

• Experience contributing to Ethereum standards, open-source crypto projects, AA frameworks or wallets

We are committed to equal employment opportunity and believe that diverse teams build better products. All qualified applicants will receive consideration without regard to any protected characteristic under applicable law.