Senior Engineer, Custody Engineering (Tokenization)

Bullish; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

Bullish is seeking a Software Engineer with deep expertise in smart contract development to enhance our tokenization strategies and support the lifecycle of digital assets. Candidates should have a minimum of 5 years' experience in software engineering, with advanced skills in Solidity and TypeScript.

This role offers the opportunity to work in an innovative environment that values technical excellence and secure practices in a fast-evolving industry. You'll collaborate with cross-functional teams to drive complex digital asset solutions.

Qualifications

• 5+ years of software engineering experience delivering complex systems in production.
• Expert-level fluency in secure public chain smart contract development.
• Strong command of TypeScript for backend development.

Responsibilities

• Drive tokenization features from concept through deployment.
• Own the technical execution for the digital asset lifecycle.
• Lead the design, implementation, and testing of smart contracts.

Skills

Software engineering

Smart contract development (Solidity, EVM)

TypeScript

Web3 development tooling

Security mindset

Education

Degree in Computer Science, Engineering, or related field

Tools

OpenZeppelin

Foundry

Hardhat

Job description

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. Bullish Exchange is regulated in Germany, Hong Kong, and Gibraltar.
• 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. You will scale those systems and ship on-chain features whose impact is visible to the business directly.

What You'll Do

• Drive tokenization features from concept through deployment, scaling the digital asset architecture against established industry standards.
• Own the technical execution for the digital asset lifecycle, including issuance, controlled transfer, and on-chain verification.
• Lead the design, implementation, and testing of the smart contracts that hold customer assets, and coordinate the audit process end‑to‑end.
• Build and maintain the off‑chain integration layer, with secure, reliable communication between the blockchain and internal systems.
• Partner with product and operational compliance teams to translate cryptographic and security requirements into engineering solutions.

What You'll Bring

• 5+ years of software engineering experience delivering complex systems in production.
• 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.
• Strong command of TypeScript for backend development, API integration, and building off‑chain indexing services.
• Hands‑on experience with modern Web3 development tooling such as Foundry or Hardhat, and integration libraries such as Viem or Ethers.js.
• Expert‑level knowledge of smart contract token standards and the surrounding ecosystem’s intricacies.
• A paranoid security mindset, with proven expertise preventing and mitigating common smart contract vulnerability patterns (re‑entrancy, oracle manipulation, access control flaws) and managing the audit process.
• 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.
• Experience with advanced wallet architectures such as Account Abstraction (ERC‑4337) or multi‑signature frameworks.

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.