Senior Backend Python Engineer (Core Gateway)

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 expanding our engineering capabilities and looking for a Senior Backend Developer to join our Core Gateway team. This is a unique, dual-track role where you will play a central part in both the present and future of our infrastructure. You will support, maintain, and extend our existing Perl-based payment gateway ensuring stability and high performance in a live financial production environment while simultaneously leading the architecting and building of our next-generation Python microservices platform. In this role, you will work in a fast-paced environment where system performance, scalability, and 99.9% reliability are critical to our core transaction flow. Location: Remote from Portugal / Ukraine (Contractor arrangement) Reporting to: Technical Lead What you will do: Dual-Track Maintenance: Support and extend the existing Perl-based payment gateway debugging production issues and adding features while the migration is ongoing. Modernization: Design, develop, and maintain modern server-side components in Python, ensuring high performance and scalability. Integrations: Integrate third-party APIs and external payment services into both legacy and modern platform layers. 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 user impact of what you build. Engineering Standards: Participate in code reviews, uphold high code quality standards, and contribute to a culture of continuous improvement. Infrastructure: Work closely with DevOps on CI/CD pipelines, containerization, and cloud deployments. What we need: Python Expertise: 5+ years of backend engineering experience with strong Python mastery (AsyncIO and FastAPI preferred). Legacy Flexibility: Experience with Perl (or a genuine eagerness to learn and work within Perl production code). We value polyglot engineers who can read and refactor legacy code. API Mastery: Solid experience integrating third-party APIs and a deep understanding of webhooks, callbacks, and retry policies. Tech Stack: Experience with CI/CD pipelines (GitLab preferred), Docker containerization, and familiarity with AWS (Lambda, cloud services). Architecture: Exposure to event-driven architectures (Kafka, message queues, etc.). Clean & Intentional Code: We value deep engineering logic over AI-generated snippets. You should be a "clean code" advocate who can explain the reasoning behind every line you ship. Curiosity for Product: You care about the "why" behind a feature. You are interested in how a product works for the end-user and the business. English Proficiency: Strong English communication skills—both written and verbal—to collaborate across multi-functional teams. 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 payabl.er: Grow with Us: Annual Learning Budget for professional development (eligible after probation)—because your growth is our growth. 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 This is a fully remote role for candidates based in Portugal or Ukraine. 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!