"payabl. empowers businesses to grow through payments innovation and banking services. Our ambition is to expand our strong portfolio of global financial services and make them all accessible through our unified platform payabl.one. As a licensed financial company with principal membership with card schemes we specialize in global payments and multi-currency banking solutions. 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 Portugal / Ukraine (Contractor arrangement) Reporting to Engineering Lead What You'll Do Design build and maintain high-performance Python microservices (FastAPI AsyncIO) Analyze legacy systems and extract business logic into modern architectures Refactor and migrate existing modules into clean scalable and maintainable services Ensure system reliability through idempotency fault tolerance and robust error handling Design and integrate external APIs handling edge cases retries and failures Implement and manage webhooks callbacks and complex retry mechanisms Write high-quality unit and integration tests Collaborate with cross-functional teams to ensure service stability and performance Contribute to architectural discussions and continuous system improvements Take ownership of services end-to-end from design to production What We're Looking For 5+ years of backend development experience with strong Python expertise Deep knowledge of AsyncIO and FastAPI Experience building non-blocking high-reliability microservices Strong experience with relational databases (MySQL PostgreSQL) Solid understanding of API design and third-party integrations Experience implementing webhooks callbacks and retry strategies Strong testing practices (unit and integration testing) Ability to work with legacy systems and migrate them into modern architectures Strong analytical and problem-solving skills Ownership mindset and ability to work autonomously within a defined architecture Nice to Have Experience with PHP Perl or JavaScript Familiarity with Kafka Redis or event-driven architectures Exposure to CI/CD pipelines Docker and Kubernetes Experience in fintech payments or e-commerce domains Knowledge of 3DS tokenization or payment gateway integrations Proven experience migrating systems across technologies or paradigms Engineering Culture & Environment Clear architectural direction with full ownership of implementation Strong emphasis on engineering quality reliability and accountability Open to new tools ideas and technologies that bring measurable value Collaborative environment with room to influence technical decisions Dedicated DevOps support with opportunities to contribute if desired What To Expect A balanced role between building new services and modernizing legacy systems Complex real-world engineering challenges in a high-reliability environment Opportunity to shape the evolution of a modern service-based architecture A team that values autonomy ownership and pragmatic problem-solving 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 Why Join payabl.? Work on high-impact systems in a fast-growing fintech environment Be part of a team that values ownership adaptability and engineering excellence Help modernize and scale a platform handling real-world financial operations Contribute to meaningful technical decisions and system evolution 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"