Director, Senior Security Architect

Bullish, Inc.; City of Westminster; On-site; GBP 110,000 - 160,000; Full time

Job summary

Bullish, Inc. is seeking a senior security architect for our London-based Security Architecture team.

You will influence secure software across web, API, mobile, and FIX platforms, shaping defenses for critical trading systems in a fast-moving crypto landscape. You will lead threat modeling, vulnerability assessments, and security tooling, while mentoring teams and collaborating with product and infrastructure to maintain industry-leading resilience.

Qualifications

• 10+ years in cybersecurity with hands-on coding
• Deep threat modeling, pen testing, code reviews
• Experience with cloud platforms (AWS/Azure/GCP) and Linux environments
• Strong knowledge of secure software development (CI/CD, Agile) and security tooling

Responsibilities

• Build threat models for critical systems and define security requirements
• Partner with Product, Engineering, and Infrastructure to ship secure software across web, API, mobile, FIX
• Lead global security initiatives and build AI-powered tooling to scale the program
• Assess vulnerabilities and provide actionable recommendations to executives
• Mentor cybersecurity and engineering teams and drive projects end-to-end

Skills

Cybersecurity

Threat modeling

Penetration testing

Code reviews

Offensive security

Public cloud

Linux

Programming languages

Tools

SAST

DAST

OWASP

Vulnerability Management

API tracing

Job description

Position Overview

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

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. As a senior member on this team, you will sit at the intersection of cutting-edge engineering and high-stakes finance, shaping how secure software is built across web, API, mobile, and FIX platforms, and pushing our security bar beyond industry-leading. This is a senior technical leadership role, a hands-on application and cloud security architect who leads through influence, deep expertise, and mentorship. If you thrive on solving complex technical challenges in a fast-moving crypto landscape and building first-of-their-kind systems, this is where you will do the most impactful work of your career. 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. A new breed of exchange.

Learn more at www.bullish.com