Smart Contract Engineer / Solidity Expert (IT) / Freelance

As a Smart Contract Engineer / Solidity Expert, you will contribute to the design and development of a secure, scalable blockchain architecture for an institutional digital assets platform. The project spans the full lifecycle of digital assets, from issuance and tokenisation through settlement-delivery, in an institutional environment with strict requirements for security, auditability and regulatory compliance. You will work at the heart of on-chain architecture design, with high standards for code quality, smart contract security and robust deployment and governance mechanisms.

What you'll do

• Design and develop advanced smart contracts in Solidity on EVM.
• Design secure, modular, scalable and maintainable on-chain architectures.
• Implement ERC-20 standards and their institutional extensions such as roles, pausability, mint/burn, and compliance hooks.
• Design and manage the lifecycle of smart contracts including deployment, upgrade patterns, migrations and controlled migration scripts.
• Participate in the design of technical governance mechanisms suited to an institutional environment.
• Establish advanced testing strategies including property-based testing, invariant testing and fuzzing.
• Ensure code quality and security through code reviews, threat modelling and security audits.
• Identify and mitigate vulnerabilities specific to smart contracts and the EVM.
• Optimise performance and gas consumption within production constraints.
• Design interactions between on-chain and off-chain components such as back-end, API, wallets, oracles, identity and access management.
• Participate in the technical design of financial asset tokenisation mechanisms and settlement-delivery / DvP models.
• Establish and manage CI/CD pipelines dedicated to smart contracts, with automated testing, quality controls and reproducible, controlled deployments.
• Document architecture choices, security mechanisms and complex technical decisions.
• Collaborate closely with Product, Architecture, Security, Legal and Compliance teams.
• Contribute to balancing technological innovation, security requirements, auditability and regulatory constraints.

What you bring

• Significant experience developing smart contracts in EVM environments, ideally on security-critical projects or in an institutional context.
• Expert-level Solidity proficiency.
• Deep knowledge of EVM execution model, storage, memory, gas, inter-contract calls and reentrancy patterns.
• Experience designing secure and modular on-chain architectures.
• Familiarity with ERC-20 standards and their extensions.
• Hands-on experience with OpenZeppelin Contracts.
• Proficiency with development frameworks such as Hardhat, Foundry or Truffle.
• Advanced testing practices including fuzzing, invariants and property-based testing.
• Experience conducting security audits and code reviews of smart contracts.
• Knowledge of threat modelling and vulnerability identification/mitigation.
• Understanding of upgrade patterns, deployment and migration strategies.
• Experience optimising performance and gas consumption.
• Experience with on-chain / off-chain integration.
• Familiarity with permissioned or institutional blockchain environments.

Nice to have

• Experience with other blockchain stacks such as Rust / Substrate or Move.
• Knowledge of applied cryptography including hashing, signatures and Merkle trees.
• Understanding of Zero-Knowledge technologies.
• Experience with financial asset tokenisation.
• Knowledge of Delivery versus Payment (DvP) models.
• Experience implementing compliance mechanisms directly within smart contracts.
• Mastery of DevSecOps / CI-CD practices applied to blockchain.
• Experience working in highly regulated environments.