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

SmartRecruiters, Inc.; Warszawa, Kraków; On-site; PLN 300,000 - 460,000; Full time

Benefits offered by this job

Flexible hours

Hybrid work model

B2B contract

Training opportunities

Job summary

InPost is building its own fintech platform from the ground up. As Principal Software Engineer, you will shape architecture, develop core fintech components, and drive AI-assisted development at scale.

The role partners with business leadership to align technical decisions with strategic goals, spanning Payments Core, Merchant, and Consumer domains. You will mentor senior engineers, craft ADRs/RFCs, and lead adoption of agentic engineering practices across multiple teams in a hybrid Poland-based

Qualifications

• 10+ years in software engineering with leadership experience.
• 5+ years designing distributed fintech systems.
• 3+ years agentic/LLM engineering in production.
• Expertise in event-driven architecture, CQRS, and saga patterns.
• Experience with REST, async, and event-based APIs.
• Strong English (B2+) and CS degree.

Responsibilities

• Serve as cross-domain technical authority across Payments Core, Merchant, and Consumer.
• Partner with Head of FinTech Engineering to turn business strategy into technical roadmap.
• Author Architecture Decision Records (ADRs) and RFCs for organisation-wide decisions.
• Own AI-assisted engineering workflows and tooling across the org.
• Mentor Staff Engineers and Engineering Managers on architecture craft.

Skills

Software architecture

Cross-team leadership

Fintech systems

Agentic/LLM engineering

API design

Cloud architecture

Technical writing

English proficiency

Education

CS/IT degree

Job description

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

• Full-time
• Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office.

InPost 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.

As Principal Software Engineer, you'll work directly with the Head of FinTech Engineering and business leadership, translating critical business goals - new product lines, regulatory deadlines, growth targets - into architecture decisions and roadmap input. You'll be the final word on cross-domain technical questions that no single team or Staff Engineer can resolve alone.

Responsibilities

• Serve as the single cross-domain technical authority, arbitrating architecture decisions across Payments Core, Merchant, and Consumer platform areas
• Partner directly with the Head of Engineering and business leadership to turn business strategy into technical roadmap input
• Author Architecture Decision Records (ADRs) and RFCs for organisation-wide decisions, with reasoning accessible to both engineers and business stakeholders
• Own the agentic engineering harness at an organisational level — design, instrument, and continuously improve AI-assisted engineering workflows based on real production data
• Identify and drive the adoption or deprecation of patterns across all teams, building the case and sequencing change without direct authorityMentor Staff Engineers and Engineering Managers on architecture craft, technical communication, and agentic tooling

Qualifications

• 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 of agentic/LLM engineering in production — shipped systems, not theoretical patterns
• Deep knowledge of distributed systems architecture: event sourcing, CQRS, domain events, saga pattern
• Experience designing APIs at an organisational boundary level — REST, async, and event-based contracts
• Strong grasp of database trade-offs (relational, time-series, document, ledger-style) and cloud architecture evaluation (AWS/GCP/Azure) at organisation scale
• Hands-on experience with multi-agent orchestration, tool-use patterns, context management, and evaluation harnesses for AI-assisted engineering workflows
• Excellent technical writing for mixed audiences — ADRs and RFCs that work for engineers and business leadership alike
• English proficiency at B2 or above
• University degree in Computer Science, IT, or a 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 the 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

Company Culture & Benefits

• 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 hours
• We offer B2B type of contract