Director, Senior Security Architect

bullish; Greater London; On-site; GBP 120,000 - 160,000; Full time

Job summary

Bullish in London is seeking a senior cybersecurity architect to secure our trading and data platforms. You will lead threat modeling, design secure software across web, API, and trading platforms, and guide cross-functional teams in a fast-paced environment.

Candidates bring 10+ years in cybersecurity with hands-on coding, cloud experience, and expertise in security tooling. On-site role based in SoHo, London, reporting to the CISO Americas.

Qualifications

• 10+ years in cybersecurity with hands-on coding and threat modeling.
• Strong knowledge of network protocols, cryptography, and cloud platforms.
• Experience with secure software development and security tooling.

Responsibilities

• Build complex threat models for critical systems and establish defenses.
• Collaborate with Product, Engineering, and Infrastructure to ship secure software.
• Lead global security initiatives and build AI-powered tooling for efficiency.
• Assess vulnerabilities and deliver actionable recommendations with KPIs.
• Drive high-impact projects in a dynamic, fast-paced environment.
• Provide technical leadership and mentorship to teams.

Skills

Cybersecurity expertise

Threat modeling

Coding experience

Cloud platforms

Security tooling

Communication skills

Independent contributor

Tools

SAST tools

DAST tools

CI/CD tooling

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:

CISO Americas

Position Overview

At Bullish, security is not a checkpoint, it is the foundation of trust that lets people move billions across our markets with confidence. The Bullish Security Architecture team secures Bullish Global, including the Bullish Exchange, Bullish Liquidity Services, CoinDesk Indices, CoinDesk Data, CoinDesk Media, and CoinDesk Events, designing the defenses that keep our mission-critical trading systems and other business lines resilient against the most capable adversaries in the world.

This position is based in SoHo London and will be required to work full-time onsite.

Responsibilities:

• Build complex threat models for critical systems and establish industry-leading cybersecurity requirements to turn ambiguity into clear, prioritized defenses.
• Partner closely with Product, Engineering, and Infrastructure teams to design and ship secure software across web, API, mobile, FIX, and trading platforms.
• Lead complex global security initiatives, build custom AI-powered tooling to maximize efficiency and scale the cybersecurity program.
• Assess vulnerability risks, deliver actionable recommendations across all technical levels, and track health metrics and KPIs for executive reporting.
• Drive high-impact projects and adapt to evolving business needs within a dynamic, fast-paced environment.
• Provide technical leadership and mentorship to the cybersecurity and engineering teams.

Experience & Qualifications:

• 10+ years in cybersecurity, including 5+ years of hands‑on coding, alongside deep expertise in threat modeling, pen testing, code reviews, and offensive security methodologies.
• Strong foundation in network protocols (IP, DNS, HTTP, SSL/TLS), cryptography (PKI, encryption at rest/in motion), Linux environments, and public cloud platforms (AWS, Azure, or GCP).
• Proficient in programming languages like C/C++, Java, JS, Python, Go, or Rust
• Possess a deep understanding of common vulnerability frameworks (OWASP Top 10, SANS CWE Top 25).
• Solid grasp of enterprise software development, Agile, CI/CD pipelines, and security tooling (SAST, DAST, OSA, Vulnerability Management, API traceability).
• Excellent ability to convey complex technical risks to non-technical executives and engineers and build strong cross-functional partnerships.
• A strong individual contributor with ability to drive projects independently from conception to complete with minimal oversight.

Nice to Have:

• A restless drive to secure systems and continuously learn new technologies.
• Experience securing trading, financial-market, or other regulated, high-stakes systems.
• Relevant certifications, such as security architecture certifications (e.g. SABSA, TOGAF), offensive security (e.g. OSCP, OSCE, SANS, CREST) and cloud security specialty certifications (AWS, Azure, or GCP).

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.