Senior Staff Backend Engineer - Fintech Platform (Hybrid)

InPost Group; Warszawa; Hybrid; PLN 320,000 - 520,000; Full time

Benefits offered by this job

Hybrid work model

Diverse international environment

Training opportunities

Flexible hours

B2B contract

Job summary

InPost Group is seeking a Staff Software Engineer, Backend for Fintech Engineering to define technical direction across Payments Core, Merchant, or Consumer domains. You will architect backend systems, author ADRs/RFCs, and guide cross-team engineers while leveraging agentic engineering practices in a data-driven way.

The role requires hands-on fintech backend expertise, 8+ years in software engineering with leadership experience, and fluency in English.

Qualifications

• 8+ years in software engineering, including 2+ years in cross-team technical leadership or architecture authority
• 3+ years designing distributed payments or fintech systems
• Hands-on experience with multiple tech stacks and backend
• Solid grounding in distributed systems architecture - event sourcing, CQRS, domain events, saga pattern
• Experience designing APIs at service-boundary level - REST, async, and event-based contracts
• Comfort 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, iteration
• Working knowledge of LLM tool-use patterns and context management in engineering workflows
• Excellent technical writing - ADRs, RFCs, and design docs for multiple audiences
• English proficiency at B2 or above

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 teams
• Author Architecture Decision Records (ADRs) and RFCs, facilitating technical decision-making across teams with documented reasoning and clear trade-off analysis
• Evaluate and decide on fundamental technology trade-offs: database selection, cloud services, message broker topology, and consistency models appropriate for financial data
• Own the evolution of the agentic development harness -instrument it, measure adoption and friction, and drive improvements with data
• Drive org-wide technical change: identify patterns 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

Skills

Backend development

Distributed systems

Event sourcing

CQRS

Domain events

Saga pattern

API design (REST/async/event)

Cloud architecture (AWS/GCP/Azure)

Agentic engineering

LLM tooling & context

Technical writing

English (B2+)

Tools

Kafka

Job description

InPost Group is seeking a Staff Software Engineer, Backend for Fintech Engineering to define technical direction across Payments Core, Merchant, or Consumer domains. You will architect backend systems, author ADRs/RFCs, and guide cross-team engineers while leveraging agentic engineering practices in a data-driven way.

The role requires hands-on fintech backend expertise, 8+ years in software engineering with leadership experience, and fluency in English.