Senior Backend Developer; Services

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

• 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.

• 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…