Senior Security Architect in Kennington

At Anaplan, we are a team of innovators focused on optimizing business decision-making through our leading AI-infused scenario planning and analysis platform so our customers can outpace their competition and the market. What unites Anaplanners across teams and geographies is our collective commitment to our customers’ success and to our Winning Culture. Our customers rank among the who’s who in the Fortune 50. Coca-Cola, LinkedIn, Adobe, LVMH and Bayer are just a few of the 2,400+ global companies who rely on our best-in-class platform.

Our Winning Culture is the engine that drives our teams of innovators. We champion diversity of thought and ideas, we behave like leaders regardless of title, we are committed to achieving ambitious goals, and we love celebrating our wins – big and small. Supported by operating principles of being strategy-led, values-based and disciplined in execution, you’ll be inspired, connected, developed and rewarded here. Everything that makes you unique is welcome; join us and let’s build what’s next - together!

This role does the hands-on architecture work. You design the secure patterns engineering builds against, review hard problems in depth, and help make secure-by-design real across the Hyperblock and Polaris platform and the AI product surface. You work closely with the Principal Security Architect, who sets the technical bar. You own significant areas of that work and deliver them end to end. Engineers adopt good architecture because it is the better path. You will build that kind of architecture, working on problems that carry real risk.

Anaplan is not a simple SaaS application. The platform performs highly dimensional, enterprise-scale modelling with responsive recalculation and strong correctness expectations. The technical surface includes the legacy Hyperblock engine, the newer Polaris engine, and a growing set of AI products. These include CoModeler for AI-assisted model building and CoPlanner for conversational planning support.

Enterprise customers in regulated industries increasingly ask a hard question: if Anaplan is breached, can Anaplan staff or an attacker read their data? Answering it takes rigorous architecture work. We are commissioning an independent Trail of Bits assessment of exactly this. It covers end-to-end tenant isolation, the proposed BYOK design, and internal infrastructure boundaries. You will help turn findings like these into concrete design changes. That includes moving key management from legacy HSM-based designs to Vault, and extending encryption coverage to storage and data paths that lack an agreed architecture today.

What you'll do

• Produce reference architectures: design and maintain security patterns for platform and AI components, working to the standards set by the Principal.
• Contribute to identity and authorisation design: including tenant isolation, service-to-service trust, and authorisation for AI agents and analyst-style workflows.
• Apply cryptography and key management: work on encryption, BYOK and key custody. Be clear about where data is plaintext, who can use keys, and what each control protects against.
• Design AI guardrails: input and output controls, tool and authorisation boundaries, and prompt-injection and abuse defences. Draw on MITRE ATLAS and the OWASP LLM Top 10.
• Run threat models: lead them on high-risk systems, working with engineers to trace trust boundaries and compromise paths. Turn the findings into prioritised, actionable design changes.
• Support external assessments: prepare architecture evidence, join discovery sessions with engineering, and check that what is built matches what is documented.
• Improve the supply chain and attack surface: build integrity and provenance, hardened images, and less exposed surface.
• Stay hands-on: write and review designs and prototypes, and test your own work.
• Grow the practice: mentor engineers, contribute to standards, and help turn design decisions into enforceable guidance.

What we're looking for

• Solid experience in secure software architecture, with depth in at least two of: cryptography and key management, identity and authorisation, tenant isolation, and threat modelling.
• A working understanding of AI and ML security, and of how LLM-driven features change identity, authorisation, supply chain, and verification.
• The ability to design and review real systems, and to defend your decisions to strong engineers.
• A record of influencing engineers without formal authority, including when risk and delivery pressure conflict.
• Experience with enterprise-scale SaaS or cloud-first systems, ideally multi-tenant.
• Clear written and verbal communication. You can explain architecture honestly to engineers, leadership, and customers.

Nice to have

• Experience with Vault, KMS/HSM, or BYOK/HYOK designs.
• Experience designing for regulated environments, such as FedRAMP.
• Contributions to NIST, ISO, or OWASP, or talks and published research.
• An offensive grounding that you use to pressure-test designs.

Our Commitment to Diversity, Equity, Inclusion and Belonging (DEIB)

We believe attracting and retaining the best talent and fostering an inclusive culture strengthens our business. DEIB improves our workforce, enhances trust with our partners and customers, and drives business success. Build your career in a place where diversity, equity, inclusion and belonging aren’t just words on paper – this is what drives our innovation, it’s how we connect, and it contributes to what makes us a market leader. We believe in a hiring and working environment where all people are respected and valued, regardless of gender identity or expression, sexual orientation, religion, ethnicity, age, neurodiversity, disability status, citizenship, or any other aspect which makes people unique. We hire you for who you are, and we want you to bring your authentic self to work every day!

We will ensure that individuals with disabilities are provided reasonable accommodation to participate in the job application or interview process, perform essential job functions, and receive equitable benefits and all privileges of employment. Please contact us to request accommodation.