Principal Software Engineer - Fintech Platform (m/f/n)
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Before you apply
LocationWarsaw/Cracow, pl
Work modehybrid
Typefull-time
SeniorityLead
Experience10+ yrs
Company size1,001–5,000 people
PostedOct 6, 2026 · 4w ago
Verified live1d ago
At a glanceSummarised by Seekless from the posting.
10+ years in software engineering
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
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
University degree in Computer Science, IT, or a related field
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
English proficiency at B2 or above
Polish language skills
We offer B2B type of contract
Skills
LLM
Python
AWS
GCP
Azure
REST
event sourcing
CQRS
event-driven
relational databases
time-series databases
document databases
ledger databases
multi-agent orchestration
tool-use patterns
context management
evaluation harnesses
Benefits
Flexible hours
Company Description
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.
Job Description
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.
→ Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office.
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 authority
•
Mentor 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
•
Polish 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 hours
•
We offer B2B type of contract