Lead Engineer, Custody Engineering (Tokenization) in London

About Bullish

Bullish is an institutionally focused global digital asset platform that provides market infrastructure and information services. These include:

• Bullish Exchange – a regulated and institutionally focused digital assets spot and derivatives exchange, integrating a high-performance central limit order book matching engine with automated market making to provide deep and predictable liquidity.
• CoinDesk Indices – a collection of tradable proprietary and single-asset benchmarks and indices that track the performance of digital assets for global institutions in the digital assets and traditional finance industries.
• CoinDesk Data - a broad suite of digital assets market data and analytics, providing real-time insights into prices, trends, and market dynamics.
• CoinDesk Insights – a digital asset media and events provider and operator of Coindesk.com, a digital media platform that covers news and insights about digital assets, the underlying markets, policy, and blockchain technology.

Reports to: Director, Engineering

Engineering Organization & Culture

At Bullish, we are engineering the institutional standard for the digital asset industry. Our mission is to build a platform centered on security and compliance, requiring a commitment to technical excellence that extends beyond delivering code. As a global organization, we set a high bar for those driven to do their best work alongside experienced, deeply specialized peers.

Engineers here treat development as a craft and own the outcome from concept to deployment. Our teams bring structure to ambiguity and shape the frameworks that support a global organization. We refuse to compromise on quality and seek problem solvers who thrive on complex technical challenges with real market consequences.

The Team: Custody Engineering

The Custody Engineering team builds the systems that safeguard user assets, architecting secure and compliant infrastructure for the full lifecycle of funds. Our technical scope spans blockchain development, smart contracts, oracles, and the full-stack systems that power them. We operate with a high degree of autonomy and ownership over core infrastructure, connecting blockchain technology with institutional-grade stability.

With the core architecture in place, the team is now heavily focused on advancing the tokenization strategy. As Lead, you will own the technical roadmap, evolve the foundational architecture using proven standards to keep security risk low, and guide the team as the systems scale. The work ships features whose impact is visible to the business directly.

What You'll Do

• Drive the evolution of the foundational architecture and engineering roadmap, leading the project's scaling and tokenization phases using established industry standards.
• Serve as the technical owner for the full tokenization lifecycle, including asset issuance, controlled transfer, settlement mechanics, and on-chain verification.
• Lead the secure design, implementation, and audit of the smart contracts that hold customer assets, and the backend for workflows interacting with the smart contracts.
• Define and enforce auditable security controls (e.g., policy engines, governance rules) that meet institutional standards for asset safety and regulatory compliance.
• Act as the primary cross-functional technical interface, translating cryptographic and security requirements into actionable engineering work for engineering, product, and operational compliance teams.
• Mentor a team of engineers and set the standard for code quality, security review, and engineering judgment.

What You'll Bring

• 6+ years of experience architecting and scaling production-grade systems. Proven ability to lead cross-functional technical initiatives and mentor high-performing engineering teams to deliver high-impact solutions.
• Expert-level fluency in secure public chain smart contract development, such as Solidity and the Ethereum Virtual Machine (EVM), with command of industry-standard security frameworks and libraries such as OpenZeppelin.
• Deep, authoritative knowledge of token standards (e.g. ERC-20, ERC-3643, Token-2022) and advanced wallet and custody architectures (e.g., ERC-4337 Account Abstraction, Gnosis Safe).
• Strong command of architecting secure off-chain services (e.g. in TypeScript), APIs, and event indexers.
• Hands-on depth with modern Web3 development and testing frameworks (e.g., Foundry, Hardhat) and interaction libraries (e.g., Viem, Ethers.js).
• A paranoid security mindset, with proven expertise preventing and mitigating common smart contract vulnerability patterns (re-entrancy, oracle manipulation, access control flaws), use of static analysis and fuzzing tools, and a track record of leading teams through smart contract audits.
• The ability to communicate protocol logic and security trade-offs to both technical and non-technical stakeholders across global teams.
• Degree in Computer Science, Engineering, or a related technical field (or equivalent professional experience).

Nice to Haves

• Engineering experience within the finance or high-security sector.
• Familiarity with SVM/Solana or Daml/Canton smart contract and application development.
• Familiarity with C++ to interface with broader platform systems.
• Fluency in modern key management paradigms (e.g., MPC, HSM) and applied cryptography specific to digital assets.
• Familiarity with institutional-grade digital asset custody environments.

Bullish is proud to be an equal opportunity employer. We are fast evolving and striving towards being a globally-diverse community. With integrity at our core, our success is driven by a talented team of individuals and the different perspectives they are encouraged to bring to work every day.