Staff Backend Software Engineer - Fintech Platform

Company Description InPost Group is an innovative European out of home deliveries company, revolutionizing the way parcels are delivered to customers. With operations across several countries, our network of intelligent lockers provides customers with a fast, convenient, and secure delivery option. InPost Group is a publicly traded company, with a market capitalization of about $5 billion as of March 2023. With over 10,000 people worldwide, InPost Group is one of the largest out of home delivery providers in Europe, committed to providing sustainable and efficient delivery solutions to meet the evolving needs of customers in today's rapidly changing landscape. We are a team that builds the best FMCG e-commerce in Poland. We already have over 300,000 products in our offer, we work with over 300 sellers, and our mobile application has already been downloaded by almost 1.5 million users in Poland. Due to the fact that our product consists of many elements that must work together efficiently and be managed effectively, we are looking for experienced consumer-focused (Web / Mobile App products) engineering leaders to join us in that journey - heavily influence our future platform build, improve processes and help us deliver best customer experience in the market across all types of devices. Job Description 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 the backend technical architecture for your area: domain boundaries, event contracts, state machine patterns, data consistency models, and cross-service API design across multiple teamsAuthor Architecture Decision Records (ADRs) and RFCs, facilitating technical decision-making across teams with documented reasoning and clear trade-off analysisEvaluate and decide on fundamental technology trade-offs: database selection, cloud services, message broker topology, and consistency models appropriate for financial dataOwn the evolution of the agentic development harness - instrument it, measure adoption and friction, and drive improvements with dataDrive org-wide technical change: identify patterns to adopt or deprecate broadly, build the case, and see adoption through across teams without direct authorityProvide technical input into product strategy; mentor Staff-track engineers through design reviews, pairing, and technical writing feedback Qualifications 8+ years in software engineering, including 2+ years in cross-team technical leadership or architecture authority3+ years designing distributed payments or fintech systemsHands-on experience with multiple tech stacks and expertise in backendSolid grounding in distributed systems architecture - event sourcing, CQRS, domain events, saga pattern - and state machine / financial entity lifecycle designExperience designing APIs at service-boundary level - REST, async, and event-based contractsComfort with database trade-off reasoning (relational, time-series, document, ledger-style) and cloud architecture evaluation (AWS/GCP/Azure)Experience designing or evolving an agentic engineering harness — instrumentation, adoption measurement, iterationWorking knowledge of LLM tool-use patterns and context management in engineering workflowsExcellent technical writing - ADRs, RFCs, and design docs for multiple audiencesEnglish proficiency at B2 or above Nice to have: 2+ years in platform or internal developer tooling engineering1+ years of agentic/LLM system design experience2+ years in BNPL or lending domain architecturePCI DSS / PSD2 architecture compliance experience from the design phaseKafka or equivalent streaming architecture experience at scaleOpen-source contributions or technical publishingPolish language skills Additional Information Opportunity to work in a diverse, international, and cross-functional environment, along with leading experts. You work and learn from a senior leader and their leadership team, expanding your experience and exposure in the e-commerce and logistics industries.  InPost is a growing company that offers its people an increasing number of opportunities in several locations in Europe. Fulfilling careers with a range of benefits for people and investing in providing training opportunities for their development. You will feel a part of the InPost community that makes an impact on sustainability, convenient deliveries, and the circular economy every day. Excellent working environment and flexible hoursWe offer B2B type of contract