Senior Full Stack Engineer

Ciklum is looking for a Senior Full Stack Engineer to join our team in Poland.

We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts and product owners, we engineer technology that redefines industries and shapes the way people live.

About the role:

As a Senior Full Stack Engineer, you'll become a part of a cross-functional development team engineering experience of tomorrow. In this role, you will become part of a small, senior product engineering team for an established US mental health platform where clients book licensed psychologists and psychotherapists, complete with US insurance integrations and subscription billing. You will take full end-to-end ownership of product features-from frontend architecture to backend services and cloud deployment-leveraging a modern stack based on React, TypeScript, Python, PostgreSQL, and Google Cloud Platform (GCP).

Responsibilities:

• End-to-End Feature Delivery: Design, implement, and deploy robust full-stack features from initial concept through production rollout
• Frontend Architecture: Own and evolve the frontend architecture, including component libraries, design systems, state management, and clear module boundaries for the engineering team
• Backend & API Development: Build and maintain scalable backend services and APIs (REST, GraphQL, or gRPC), covering authentication, RBAC, billing workflows, and audit logging
• Code Quality & Testing: Write clean, secure, and maintainable code; establish and drive a risk-based testing strategy with strong end-to-end test coverage
• Internal Tooling & AI Adoption: Develop internal productivity tooling (CLIs, agent-based workflows) and proactively utilize AI coding tools as force multipliers
• Engineering Excellence & Mentorship: Conduct rigorous code reviews, champion engineering best practices, and mentor teammates in adopting modern standards
• Cross-functional Collaboration: Partner closely with product management, UX/UI design, and executive leadership to shape the roadmap and guide core UX decisions

Requirements:

• Experience: 6+ years of commercial software engineering experience, with a proven track record of building and scaling SaaS products as a Full Stack Engineer
• Communication: Upper-Intermediate to Advanced (Fluent) English proficiency, both written and spoken
• Software Design & Architecture:
  • Demonstrated experience designing solutions for complex features and maintaining comprehensive technical documentation
  • Deep understanding of API architectural styles (monolith, microservices, serverless), design patterns, and engineering standards
  • Hands-on experience defining frontend architecture (design systems, shared component libraries) utilized by multiple developers
  • Proven ownership of critical product domains from discovery to launch (e.g., onboarding, billing, access control)
• Software Development:
  • Strong proficiency in TypeScript, modern JavaScript, HTML5, CSS3, and advanced React patterns
  • Solid background in Node.js or Python building high-performance backend services; willingness and ability to work primarily in a Python / FastAPI codebase
  • Strong relational database skills in PostgreSQL (data modeling, schema design, complex queries, and aggregations)
  • Practical commercial experience with distributed systems and event-driven patterns using message brokers (Kafka, RabbitMQ, SQS, etc.)
• Quality Assurance:
  • Hands-on experience with modern testing frameworks across the stack (e.g., Jest, Vitest, Playwright, Cypress, pytest)
  • Ability to define, track, and maintain code quality metrics; familiarity with observability, monitoring, and logging tools
• DevOps & Cloud Deployment:
  • Practical knowledge of containerization (Docker) and CI/CD pipelines (GitLab CI, GitHub Actions)
  • Experience deploying, configuring, and operating backend services on a public cloud (GCP or AWS)
• Ways of Working:
  • High degree of autonomy and seniority: ability to lead a problem space independently, balance technical trade-offs, and communicate effectively with both technical and non-technical stakeholders
  • Availability for a 3-4 hour daily working overlap with US Pacific Time (PT) for key ceremonies, planning, and stand-ups

Desirable:

• Prior experience as a Founding Engineer, Tech Lead, or core team member at an early-stage or growth-stage product company
• Domain knowledge in HealthTech / Digital Health (HIPAA compliance, health insurance workflows) or FinTech / Payments
• Production experience with Stripe billing, subscription life-cycles, and payment processing
• Familiarity with Micro-frontends, Next.js, React Native, or Expo
• Hands-on experience with Go, Elixir / Phoenix, or gRPC
• Exposure to Infrastructure as Code (Terraform) and container orchestration (Kubernetes / GKE)
• Experience developing MCP servers, CLI developer tools, or LLM-assisted internal automations
• Active involvement in hiring, conducting technical interviews, and mentoring junior/middle engineers
• Degree in Computer Science, Software Engineering, or a related technical field

What’s in it for you?

• Strong community: Work alongside top professionals in a friendly, open-door environment
• Growth focus: Take on large-scale projects with a global impact and expand your expertise
• Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications
• Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies
• Flexibility: Enjoy flexibility - full remote working possibilities
• Care: We've got you covered with company-paid premium medical package through Luxmed
• Benefits: Access the MyBenefit cafeteria platform, allowing you to choose perks that best suit your lifestyle and needs

About us:

At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress.

With delivery centers in Wrocław and Gdańsk, our 300+ professionals in Poland drive forward-thinking solutions for global clients. Join a community where collaboration sparks innovation-and your impact reaches millions.

Explore, empower, engineer with Ciklum!

Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum.