Principal Software Engineer - Fintech Platform (m/f/n)

As Principal Software Engineer, you'll work directly with the Head of FinTech Engineering and business leadership, translating critical business goals - new product lines, regulatory deadlines, growth targets - into architecture decisions and roadmap input. You'll be the final word on cross-domain technical questions that no single team or Staff Engineer can resolve alone. → Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office . Responsibilities: • Serve as the single cross-domain technical authority, arbitrating architecture decisions across Payments Core, Merchant, and Consumer platform areas • Partner directly with the Head of Engineering and business leadership to turn business strategy into technical roadmap input • Author Architecture Decision Records (ADRs) and RFCs for organisation-wide decisions, with reasoning accessible to both engineers and business stakeholders • Own the agentic engineering harness at an organisational level — design, instrument, and continuously improve AI-assisted engineering workflows based on real production data • Identify and drive the adoption or deprecation of patterns across all teams, building the case and sequencing change without direct authority • Mentor Staff Engineers and Engineering Managers on architecture craft, technical communication, and agentic tooling