When recruiting a blockchain engineer, a deep understanding of blockchain technology, including architecture, consensus, encryption and smart contracts, is crucial. The candidate should demonstrate experience in developing and deploying decentralised applications (DApps) on various blockchain platforms such as Ethereum, Hyperledger, and Solana.

The candidate should have hands-on experience in designing and implementing smart contracts, using languages such as Solidity for Ethereum or Vyper. The ability to write secure and optimised contracts is essential to ensure the performance and security of blockchain applications.

It is important for a blockchain engineer to have a strong foundation in cryptography, including asymmetric encryption, symmetric encryption, hash functions and digital signatures. These skills are key to securing transactions and data on the blockchain network.

The candidate should be proficient in using the tools and frameworks necessary to develop and test blockchain applications, such as Truffle, Hardhat, Ganache, and be able to use web3.js or ethers.js libraries to interact with the blockchain.

Understanding and experience in implementing blockchain scaling solutions, such as sharding, layer-2 solutions or sidechains, are important for an engineer to contribute to blockchain projects that require high bandwidth and low latency.

A blockchain engineer often works in interdisciplinary teams. Good communication skills and the ability to work as part of a team are key to collaborating effectively with developers, systems analysts, project managers and other project stakeholders.