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

InPost is building its own fintech platform from the ground up as a large-scale, international initiative. The company is establishing a lean, highly effective engineering organization in Poland focused on AI-native engineering.

• 10+ years in software engineering, including 5+ years in cross-team technical leadership or architecture authority
• 5+ years designing distributed payments or fintech systems
• 3+ years experience deploying agentic/LLM engineering in production
• Deep knowledge of distributed systems architecture: event sourcing, CQRS, domain events, saga pattern
• Experience designing APIs at organizational boundary level (REST, async, event-based contracts)
• Strong understanding of database trade-offs (relational, time-series, document, ledger-style) and cloud architectures (AWS/GCP/Azure) at organization scale
• Hands-on experience with multi-agent orchestration, tool-use patterns, context management, and evaluation harnesses for AI-assisted workflows
• Excellent technical writing skills for mixed audiences, including ADRs and RFCs
• English proficiency at B2 or above
• University degree in Computer Science, IT, or related field

Nice to have:

• 3+ years in platform or internal developer tooling engineering
• 1+ years of agentic/LLM system design experience
• PCI DSS / PSD2 architecture compliance experience from design phase
• BNPL or lending domain architecture experience
• Open-source contributions or external technical publishing
• Experience building or scaling an internal developer platform
• Formal mentorship of Staff-level or EM-track engineers
• Polish language skills

• Serve as the single cross-domain technical authority for architecture decisions across Payments Core, Merchant, and Consumer platform areas
• Translate business strategy into technical roadmap input in partnership with Head of Engineering and business leadership
• Author Architecture Decision Records (ADRs) and RFCs accessible to both engineers and business stakeholders
• Own and continuously improve the agentic engineering harness at an organizational level based on production data
• Identify and drive adoption or deprecation of patterns across all teams without direct authority
• Mentor Staff Engineers and Engineering Managers on architecture craft, technical communication, and agentic tooling