"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 Initial Interview – A 30–40 minute online interview with a Talent Acquisition Partner where we explore your experience motivations and overall fit for our modernization culture. Step 2 Live Technical Assessment Interview – A 90-minute live coding challenge and system design discussion with our field technical experts. Step 3 Final Discussion – A 30-minute conversation with our CTO CPO and TA Partner to discuss behavioral traits background and clarify the domain scope. 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! Please review our Privacy Policy to understand how we process your personal data during the recruitment process https//payabl.com/privacy-policy"