Staff Software Engineer, Frontend - Fintech Platform (m/f/n)

InPost's FinTech Platform team is looking for a Staff Engineer to define the technical direction for one of our platform areas - Payments Core, Merchant, or Consumer. You'll multiply team output through architecture clarity, engineering standards, and cross-team technical leadership, while helping evolve our agentic engineering harness in a data-driven way.
You'll own the evolution of fundamental technology decisions across your area - ensuring they're sound, defensible, and viable for the long term - and act as the technical throughline between engineering teams, product strategy, and the organisation's wider architecture standards.
→ Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office.
Responsibilities:
Define and maintain frontend architecture across the area: component architecture, design-system boundaries, micro-frontend patterns, client-side state management, and performance budgets across multiple teams
Author Architecture Decision Records (ADRs) and RFCs for frontend decisions, facilitating technical decision-making across teams with documented reasoning and clear trade-off analysis
Evaluate and decide on fundamental frontend technology trade-offs: framework and library selection, build tooling, rendering strategy (SSR / CSR / ISR), and accessibility standards
Own the evolution of the agentic development harness for frontend workflows — instrument it, measure adoption and friction, and drive improvements with data
Drive org-wide technical change: identify frontend patterns and design-system components to adopt or deprecate broadly, build the case, and see adoption through across teams without direct authority
Provide technical input into product strategy; mentor Staff-track engineers through design reviews, pairing, and technical writing feedback
8+ years in software engineering, including 2+ years in cross-team technical leadership or architecture authority
3+ years building customer-facing or merchant-facing products in payments or fintech
Expert-level experience with a modern frontend framework (e.g. React) and TypeScript at scale
Design-system and component-architecture experience across multiple teams or products
Micro-frontend architecture and client-side state management patterns
Performance engineering expertise — Core Web Vitals, bundle optimisation, and rendering-strategy trade-offs (SSR / CSR / ISR)
Accessibility standards (WCAG) built into architecture, not bolted on
API-consumption patterns: REST, GraphQL, async, and event-based contracts
Experience designing or evolving an agentic engineering harness for frontend workflows — instrumentation, adoption measurement, iteration
Excellent technical writing — ADRs, RFCs, and design docs for multiple audiences
English proficiency at B2 or above
University degree in Computer Science, IT, or a related field
Nice to have:
2+ years in platform or internal developer tooling engineering
1+ years of agentic/LLM system design experience
2+ years in BNPL or lending domain product experience
Mobile app architecture (e.g. React Native) alongside web
Real-time UI patterns (WebSockets, streaming updates)
Internationalisation / localisation architecture at scale
Open-source contributions or technical publishing
Polish language skills

Employment type
Full-time

Work arrangement
Hybrid