Principal Software Engineer London/Hybrid Working to £130,000 + Bonus + Excellent Benefits PostgreSQL, Express, React, Node.js Outstanding opportunity for a Principal Engineer with the PERN stack (PostgreSQL, Express, React, Node.js) and significant Martech or Adtech experience to join one of the UK''s top online marketplaces. As a Principal Engineer, you''ll define the technical vision and strategy, driving innovation and leading technological change across the business. This role will join their Martech and Adtech function who create tooling to drive conversion and revenue via marketing, advertising, and external partnerships. This is an individual contributor level role. Ideally, we are looking for any level of experience with a Martech stack (CRM, CMS, loyalty/referrals/rewards), opinion on go to market strategy, and a genuine full stack person who can design a full system. This is your chance to own the full life cycle of implementing and maintaining high-performance payment processing systems and secure transaction processing. Key Responsibilities: Lead innovation across teams, identifying and championing technical initiatives. Define roadmaps and guide engineers from different departments. Shape the future technical strategy with a forward-looking vision. Mentor and inspire engineers, fostering a culture of excellence and knowledge sharing. Actively participate in company-level decision-making and cross-functional initiatives. Key Requirements: Extensive ..... full job details .....