Senior Backend Engineer - FinTech Engineering (M/F/N)

InPost Pay is building its own fintech platform from the ground up. It’s a large-scale, international initiative where engineers will have the opportunity to shape the architecture, build core fintech components, and create solutions designed to operate at InPost’s scale. We’re building a lean, highly effective engineering organization in Poland, with AI-native engineering at its core. We’re looking for strong engineers who are comfortable with agentic engineering, from experienced professionals building complex systems and engineering tooling to a new generation of engineers who have embraced AI-driven development from the start of their careers. → Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office. We're looking for a Senior Backend Engineer to join our FinTech Platform team and help us build the next generation of payment and financial services solutions at InPost. In this role, you'll take end-to-end ownership of payment domain features, designing and building distributed backend services that power critical financial operations. You'll work in a modern engineering environment where accountability extends from product requirements through architecture, development, production monitoring, and continuous improvement. What will you work on? - designing and building event-driven backend services supporting payment authorisation, ledger management, settlement, and other financial domain processes,  - developing scalable and resilient APIs with a strong focus on reliability, security, performance, and maintainability,  - participating in the full software development lifecycle, from requirements and technical design through testing, release, and production support, - designing and maintaining structured domain events and event-driven integrations across distributed systems,  - collaborating with engineering managers and product teams to shape roadmaps, refine requirements, and influence technical direction,  - investigating incidents, performing root cause analysis, and driving continuous platform improvements,  - mentoring engineers, conducting code reviews, and promoting engineering best practices across the team.  This cooperation may be a strong match if you: - have at least 5 years of experience in backend software engineering using Java, C#/.NET, Rust, or Node.js, - have hands-on experience designing and operating distributed systems and event-driven architectures, - have delivered and maintained production services, APIs, CI/CD pipelines, and observability solutions, - understand distributed systems concepts such as consistency models, saga patterns, idempotency, and outbox patterns, - have practical experience with relational databases, preferably PostgreSQL, - are comfortable with automated testing at multiple levels, including unit, integration, and contract tests, - actively use AI-powered engineering tools such as GitHub Copilot, ChatGPT, Claude, or similar solutions in everyday development work, based on engineering best practices promoted within the team, - communicate in English at B2 level or higher.Additional advantages: - experience within payments, fintech, or regulated environments, - experience with Java and Spring Boot in production environments, - knowledge of Kafka or other streaming technologies, - familiarity with PCI DSS, PSD2, KYC/KYB, or risk decisioning systems, - experience with Docker, Kubernetes, cloud platforms, and observability tooling such as Prometheus, Grafana, or OpenTelemetry. What we offer: - the opportunity to build products that sit at the heart of InPost's growing financial services ecosystem, - ownership of business-critical solutions operating at scale, - a modern engineering environment focused on autonomy, accountability, and continuous learning, - collaboration with highly experienced product, engineering, and business teams, - access to cutting-edge technologies, event-driven architectures, and cloud-native solutions, - opportunities to shape technical standards, mentor others, and influence platform evolution, - full-time contract of employment.