Senior Backend Developer (Services)

# Senior Backend Developer (Services) > payabl. · Warsaw, Poland · Full-time · Posted 2026-06-24 **Workplace:** on_site **Department:** IT ## Description **The role is about:** We are looking for a **Senior Python Backend Developer (Services)** to join our engineering team and contribute to the evolution of our service layer architecture. This role is focused on designing and building reliable, scalable microservices while also working with and gradually transforming legacy systems. You will play a key role in extracting business logic from existing codebases and reimplementing it into modern, maintainable Python services. This is a hands-on engineering role requiring strong problem-solving skills, attention to detail, and a deep understanding of backend systems reliability. Success in this role means going beyond “it works” ensuring correctness, resilience, and long-term maintainability. - **Location:** Remote from Poland (Contractor arrangement) or Cyprus Onsite (employment arrangement) - **Reporting to:** Technical Lead **What you will do:** - **Legacy Modernisation:** Read legacy code (PHP, Perl, or JavaScript), extract the business logic, and reimplement it correctly within a modern microservices architecture. - **Reliability First:** Ensure idempotency, data integrity, and graceful error handling across all services — "almost working" is never good enough. - **Greenfield & Refactoring:** Split your time between building new features from scratch and refactoring existing legacy modules into clean, maintainable code. - **API Engineering:** Design and consume external APIs with a deep understanding of webhooks, callbacks, and complex retry policies. - **Agile Collaboration:** Maintain clean and strong English communication to effectively collaborate with multiple stakeholders across departments working in agile sprints. - **Product Thinking:** Go beyond the "what" and "how" of the code — bring a product-focused mindset to understand the business logic and end-user impact of what you build. - **Infrastructure Contribution:** Contribute to CI/CD pipelines, Docker, or Kubernetes infrastructure where relevant. If you have a passion for infra, you are more than welcome to bring it. - **Innovation:** Propose and advocate for tools or technologies that can demonstrably improve our performance, security, or development speed. **What we need:** - **Python Mastery:** 5+ years of backend engineering experience with strong Python expertise. Deep AsyncIO proficiency — you must be comfortable building non-blocking, high-reliability microservices. - **Framework Expertise:** Production-grade experience with **FastAPI** (not just familiarity). - **Databases:** Experience with MySQL and/or PostgreSQL — query design, schema understanding, and migration strategies. - **Testing Discipline:** Experience writing unit and integration tests (pytest preferred). - **API & Reliability Patterns:** Expertise in designing and consuming external APIs with a deep understanding of webhooks, callbacks, and complex retry policies. - **Ownership Mindset:** Willingness to take full ownership of high-traffic, always-up applications and operate independently within an established architectural vision. - **Confidence in Complex Systems:** Comfortable in complex distributed environments where reliability is non-negotiable. - **Clean & Intentional Code:** We value deep engineering logic over AI-generated snippets. You must be able to explain the reasoning behind every line you ship. - **Curiosity for Product:** You care about the "why" behind a feature — how it works for the end-user and what it means for the business. - **Strong English:** Both written and verbal to collaborate effectively across multi-functional teams. - **Nice to Have:** - Experience with PHP, Perl, or JavaScript — a strong bonus signal for legacy comprehension. - Kafka / Redis experience. - Docker / CI/CD / Kubernetes familiarity. - Financial industry exposure — fintech, payments, 3DS, Token Management Systems, or payment gateway integrations. - Track record of successfully migrating systems from one language or paradigm to another. **Hiring Process:** - **Step 1 – Thinking in Action (40 minutes)** Your first conversation will be with our Talent Acquisition team. We'll explore your background, career journey, motivations, and overall fit for the role. As part of this discussion, you'll also complete a short technical screening that will be reviewed by our engineering team. This stage helps us understand both your experience and how you approach technical challenges. - **Step 2 – Build in Production (60–90 minutes)** Meet with the Team Lead and technical experts for a practical assessment. Depending on the role, this may involve a live coding exercise or a real-world scenario designed to evaluate your technical skills, problem-solving approach, and ability to work through challenges similar to those faced by our teams. - **Step 3 – Final Interview (45 minutes)** The final stage is a group interview with senior members of our Technology squad, which may include the CTO, CPO, and Team Lead. Together, we'll discuss team fit, collaboration style, expectations from both sides, and any remaining questions about the role, team, or technology domain. This is also an opportunity for you to learn more about our culture and ways of working. **The perks of being a :** - **Future-Proof Your Finances:** Once you’ve passed probation, we’ll kickstart your Provident Fund to secure your future. - **Grow with Us:** Annual Learning Budget for professional development (eligible after probation)—because your growth is our growth. - **Wolt Your Way Through Lunch:** €150 monthly Wolt allowance to keep you fueled and happy. - **Stay Active Your Way:** Enjoy a SportsBenefits membership giving you access to a wide variety of gyms and sports facilities to support your active lifestyle. - **Drive in Style:** After one year with us, you may be eligible for a company car—performance and availability permitting. - **Park with Ease:** Complimentary parking space just steps from the office, so your commute is as smooth as your workday. - **Max Out Your Downtime:** 25 days of vacation + public holidays + 10 days of sick leave. - **Shop & Save:** Exclusive local discount card + tickets for exciting events like Beonix, basketball games, and more. - **Speak Like a Local:** Join free Greek language classes, twice a week, open to all team members. - **Celebrate Together:** We bring colleagues from all offices together for unforgettable company celebrations. - **Global Collaboration & Events:** Opportunities to participate in international company events and initiatives, connecting with colleagues from all regions and contributing to a truly global community _**The benefits listed above are for our Cyprus office location only, a list of benefits and contract type will be assessed subject to your location and discussed in the first interview with your Talent Acquisition Partner.**_ Let's embark on a journey to redefine the landscape of payments together. We're not just offering a role; we're inviting you to be a part of something bigger. Join our team, and let's innovate, disrupt, and lead the future of payments. Together, we can make an impact that resonates. Welcome to the team! Please review our Privacy Policy to understand how we process your personal data during the recruitment process: [](https://payabl.com/privacy-policy)[](https://payabl.com/privacy-policy) ## Apply [Apply at payabl.](https://apply.workable.com/payabl/j/614B4D004F/apply) --- Powered by [Workable](https://www.workable.com)