Senior Security Engineer in London

Spendesk is building the leading spend management platform for modern businesses, processing billions of euros across Europe and beyond.

Security is at the heart of what we do, and we’re committed to raising the bar for security in fintech.

Your Mission

You’ll be the security conscience for engineering: building tooling, training developers, and partnering with Infrastructure on secure‑by‑default solutions.

You own the technical security roadmap: partnering with the compliance team to identify risks, translating findings into actionable engineering‑native tools and processes, driving remediation, and raising the bar across the organization.

This is a pure engineering role, not governance or compliance: a separate team owns policy and risk frameworks.

It’s an individual contributor track with high influence, focused on technical depth, not people management.

You’ll mentor an Associate Security Engineer, shape practices across squads, and be the go‑to person when engineering teams need security guidance.

You’ll be hands‑on across the full security surface from day one.

As the team grows, you’ll move from day‑to‑day operations toward architecture, strategy, and mentoring, acting as the escalation point for the Associate Security Engineer.

Key Responsibilities

• Vulnerability & Incident Management
• Own and operate our bug bounty program: manage the platform, set escalation thresholds, and drive strategic improvements.
• Act as escalation point for vulnerability triage, taking the lead on complex or high‑severity findings.
• Lead security incident response: qualification, forensics (including fraud investigations), fix coordination, post‑mortem, and resolution tracking.
• Detection & SIEM
• Own our SIEM platform (Elastic Search, multi‑node Linux): architecture, detection rules, and indicators of compromise.
• Build and evolve detection coverage, focusing on signal quality over manual toil.
• Build and maintain security runbooks and operational documentation.
• Identity & Access Management
• Own IAM implementation and operations for product and infrastructure systems, downstream of corporate IT: SSO/MFA configuration, role and access‑rights implementation, periodic permission reviews, and secrets rotation.
• Work within the authentication standards set by the security governance team.
• Secure Development & Audits
• Embed security into the development lifecycle: threat modelling, secure code patterns, CI/CD hardening.
• Conduct technical security reviews of code (Type Script, Node. js, Python), infrastructure‑as‑code (Terraform), and multi‑tenant AWS environments.
• Drive security tooling in CI/CD: design and own the automated gate suite (SAST, SCA, container scanning, AI‑generated code risk detection) and ensure pipeline coverage scales with engineering growth.
• Assess and govern AI tooling adoption across engineering: define security standards for code assistants and LLM‑powered workflows, and conduct AI‑specific threat modelling.
• Coordinate and execute penetration tests and security audits: prepare environments, manage auditor relationships, drive post‑audit action plans.
• Drive remediation within the qualification rules and timeframes set by the security governance team.

Education & Influence

• Coach engineers on secure development through workshops, secure‑code guidance, and design reviews.
• Surface security risks and recommendations to engineering leadership; own the security backlog and roadmap.
• Partner with Infrastructure on secure‑by‑default solutions.
• Must‑Haves
• A track record of owning security outcomes end to end, with hands‑on experience across at least three of: code auditing, infrastructure security (AWS/Linux), penetration testing, SIEM operations, incident response.
• Ability to own a roadmap: identify priorities, build a plan, execute autonomously, and communicate progress to non‑specialists.
• Deep understanding of modern web architectures (microservices, cloud‑native, Paa S/Saa S) and where they break.
• Strong scripting and automation ability (Python, Bash, or similar).
• Experience mentoring other engineers or security practitioners.
• Excellent communication: explain a CVSS 9.8 to a PM and get them to prioritise it.
• Nice‑to‑Haves
• Experience with Elastic Search / ELK stack in production.
• Familiarity with AWS, GCP, Snowflake, Datadog, Okta.
• Knowledge of security standards and frameworks (ISO 27001, OWASP, SOC 2, PCI‑DSS).
• Experience in a regulated fintech or payments environment.
• Reverse engineering and analysis of minified/obfuscated code.

Not ticking every box? We’d still love to hear from you. If this role excites you and you believe you could contribute, we encourage you to apply.

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