Blockchain developers build and maintain decentralised applications, smart contracts, and blockchain infrastructure. The work spans protocol development, DeFi protocol engineering, NFT platforms, and enterprise blockchain solutions for industries like finance and supply chain. Most work in crypto-native companies, Web3 startups, or the blockchain divisions of banks and consultancies. A typical week involves writing and auditing Solidity contracts, reviewing tokenomics, participating in protocol governance discussions, and debugging cross-chain integrations.
Alex Petrov
Senior Blockchain Engineer
📍 London, UK✉️ alex.petrov@email.com
Summary
Senior Blockchain Engineer with 5 years of experience building DeFi protocols and smart contract systems on Ethereum and Solana. Audited 30+ smart contracts with zero critical vulnerabilities post-deployment. TVL of protocols contributed to exceeds $500M.
Work Experience
Senior Smart Contract Engineer at Aave LabsMar 2022 — Present
Develop and maintain Solidity smart contracts for Aave V3 lending protocol managing $8B+ TVL
Conduct internal security reviews and collaborate with Trail of Bits and OpenZeppelin on external audits
Blockchain Developer at ConsenSysSep 2019 — Mar 2022
Built Solidity smart contracts for MetaMask Swaps aggregator processing $1B+ monthly trading volume
Developed Hardhat testing frameworks and CI/CD pipelines for smart contract deployment automation
Blockchain Developer CVs must show your smart contract language proficiency, protocols contributed to, and security audit experience. Include TVL of protocols you have worked on and any audit outcomes.
Key Skills to Include
Solidity, Foundry/Hardhat, DeFi protocol design, smart contract auditing, EVM/Solana, cross-chain (CCIP/LayerZero), TypeScript/Rust, and gas optimisation.
Common Mistakes
Not linking to your GitHub contributions and deployed contracts. In Web3, your on-chain work is your portfolio. Include mainnet contract addresses and TVL figures for protocols you contributed to.
Formatting Tips
One to two pages. Lead with your protocol contributions and audit experience. Include a GitHub/portfolio link prominently. List blockchain platforms and TVL managed.
Average Salary — Blockchain Developer
United States
$130,000 – $220,000
United Kingdom
$90,000 – $160,000
Germany
$85,000 – $150,000
UAE / Dubai
$90,000 – $165,000
Canada
$110,000 – $185,000
Australia
$110,000 – $180,000
Figures in USD. Ranges reflect mid-level experience (3–7 years). Senior roles and major metro areas typically sit at the top of these bands.
Top 5 Interview Questions — Blockchain Developer
1Explain how a reentrancy attack works and how you prevent it.
Walk through the CEI (Checks-Effects-Interactions) pattern and OpenZeppelin's ReentrancyGuard. Mention the DAO hack if it helps illustrate — security knowledge is the primary differentiator for senior smart contract roles.
2What is your experience with smart contract auditing and testing frameworks?
Name the tools: Hardhat, Foundry, Echidna, Slither, MythX. Saying you write fuzz tests and invariant tests is significantly more impressive than saying you "write unit tests".
3How do you approach gas optimisation in Solidity?
Be specific: storage slot packing, using calldata over memory, avoiding redundant storage reads, custom errors over require strings. Walk through a real optimisation you made and what it saved.
4Tell me about a DeFi protocol or Web3 project you have built or contributed to.
Link to GitHub, a deployed contract address on Etherscan, or a live protocol. Blockchain development is one field where a public portfolio matters more than a degree — lead with it.
5How do you stay current in a space that moves as fast as blockchain?
Name specific sources: Ethereum research forums, Rekt News for security incidents, Messari, Bankless, EIP discussions on GitHub. Showing active participation in the ecosystem is highly valued.
How to Tailor Your CV
Protocol labs and DeFi native companies like Uniswap, Aave, and Chainlink look for deep Solidity or Rust (for Solana) expertise and an active on-chain presence — link your ENS address or GitHub. Crypto exchanges like Coinbase and Kraken hire blockchain engineers for infrastructure, wallet systems, and compliance tooling. Traditional finance firms like JPMorgan's Onyx division and HSBC want blockchain engineers who can bridge legacy systems with distributed ledger technology and communicate technical concepts to non-technical stakeholders.