Staff Backend Engineer

Department: Tech Team

Employment Type: Permanent Contract Staff

Location: Kraków, Poland, Hybrid

Staff Backend Engineer (Tech Lead)

Soter builds an AI platform for EHS and insurance — production agentic system, real customers, ~15 engineers (5 on AI). You'd be on a small team with high ownership.

B2B Contract | Start: ASAP | Krakow, Poland (Hybrid — 3 days in the office)

About the Role

We’re looking for a Staff Backend Engineer with a Tech Lead profile who can own significant parts of our backend platform and drive technical direction across the team. This is a hands-on engineering leadership role — you’ll architect and ship production backend services, lead technical decisions, and raise the engineering bar across the team. We care more about high agency and architectural instincts than years on a CV. If you’re excited about building scalable, cloud-native systems and want real influence on a small, fast team, this is for you.

Responsibilities

• Provide technical architecture and software engineering expert services — design scalable, secure, and high-performance backend systems (Python), including microservices and event-driven architectureAdvise on technical direction across cloud-native solutions (AWS, GCP) and containerisation (Docker, Kubernetes)
• Identify and recommend solutions to mitigate technical risks related to system performance, scalability, and maintainability
• Identify and drive refactoring opportunities to improve maintainability, scalability, and long-term system health
• Lead and mentor engineers — conduct code reviews, define and enforce good engineering practices
• Own backend services end-to-end — schema, API, deploy, on-call
• Recommend and implement automated testing frameworks (backend-first) and enforce code quality standards
• Introduce and maintain monitoring and observability practices to ensure product reliability and performance
• Own and improve CI/CD pipelines and IaC (Terraform, Ansible) — keep delivery boring and reliable
• Evaluate security vulnerabilities, provide guidance on security best practices, and ensure developed solutions are secured and threat modelled
• Collaborate closely with product managers to translate business requirements into technical solutions

Must-Have Requirements

• Proven hands-on experience in backend development — Python is the primary language
• Strong background in microservices architecture and event-driven systems
• Extensive experience developing and maintaining cloud-based SaaS applications (AWS and/or GCP)
• Deep understanding of clean architecture, clean design, and SOLID principles — able to reason about system design clearly, verbally and visually, and apply these to real-world distributed systems
• Experience with containerisation technologies — Docker and Kubernetes
• Understands what automated tests are for, knows which type applies where (unit, integration, e2e), and can fit testing strategy into the overall architecture picture
• Experience with IaC tools (Terraform, Ansible) for managing cloud infrastructure
• Demonstrated ability to introduce and maintain monitoring and observability practices
• Solid backend fundamentals: APIs, SQL database design and optimisation
• Demonstrated ability to work autonomously and own systems end-to-end
• Demonstrated ability to lead and mentor engineers, conduct code reviews, and promote best practices
• Strong product focus with the ability to translate business requirements into technical solutions
• Daily hands-on use of AI development tools (Cursor, Claude Code, Copilot, or similar) — this is a hard requirement; we care about how you use the tool, not which one
• Fluent English (written and verbal)
• Self-driven, product-minded, high agency — no hand-holding needed

Must-Have (Autonomy)

Has owned a non-trivial backend service or platform component end-to-end for 12+ months — design, deployment, on-call, iteration on real user feedback

What You'll Work On in Your First 3 Months

• Audit and improve the architecture of our core backend services — identify and implement quick wins in performance and scalability
• Take ownership of at least one major backend service end-to-end — schema, API, deploy, on-call
• Establish or improve observability practices so system health is visible and actionable
• Conduct code reviews and introduce engineering standards that raise the bar across the team

Nice to Have

• Experience working with multi-agent AI systems
• Understanding of integration patterns with external systems
• Node.js backend experience
• Experience with LLM-powered features or AI-adjacent backend work
• Hands-on frontend experience with TypeScript, React, and Next.js

Why Join Us

• Join a small team of passionate engineers dedicated to innovation and excellence
• Work on a product that genuinely improves people's lives and workplace safety
• Experience a startup culture: fast-paced, close collaboration, real influence on key decisions
• Short feedback loops — ship fast, learn fast
• Minimal bureaucracy — focus on what matters: building great software
• AI-first engineering culture — we embrace and invest in AI-augmented development