CareerPlan

Principal Security Engineer (AppSec)

LondonFull-time2026-10-15 → 2026-11-09

Core

Principal Security Engineer leading the transformation of the Software Development Life Cycle (SDLC) into a Secure SDLC for a regulated European fintech platform serving local businesses.

Role type

Principal Security Engineer (AppSec)

Builds

Secure SDLC patterns, policy-as-code pipelines, threat modelling frameworks, and security tooling for a payments platform.

Domain

Fintech / Payments / Regulated Financial Services

Required skills

Application security expertise, SDLC to SSDLC transformation, attacker mindset, fundamental security understanding, communication with non-technical audiences, team collaboration

Preferred skills

Penetration testing, regulated environment operations (PCI-DSS, ISO27001, DORA), engineering mindset, Go programming, cloud security, applied cryptography

Technologies

Go, SAST, SCA, secrets management, DAST

Responsibilities

Map delivery paths and baseline application estate risk, embed with engineering teams for threat modelling, design and roll out SSDLC controls, build pipeline-embedded security checks, create security champions network and enablement, shift security left via secure defaults and templates.

Seniority

Principal, strategy & mentorship