Senior Backend Python Engineer (Gateway)

The role is about:

The Gateway Related Projects team is committed to designing, developing, and implementing payment solutions that guarantee stable and consistent payment processing. Our goal is to create successful products and establish a reputation as a dependable partner for our clients.

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 or Poland (Contractor arrangement)
• Reporting to: Technical Lead

What you will do:

• Dual-Track Engineering: Support and extend the existing Perl-based payment gateway while simultaneously designing and building high-performance microservices in Python.
• System Modernization: Architect and implement scalable, distributed Python services to replace legacy components, ensuring reliability under high-load production environments.
• High-Stakes Integrations: Integrate and manage complex third-party APIs and external payment services, ensuring seamless transaction flows and robust error handling.
• Technical Leadership: Lead code reviews, drive engineering best practices, and identify system bottlenecks to continuously improve performance and scalability.
• Architecture & Deployment: Collaborate with DevOps to improve CI/CD pipelines (GitLab) and architect solutions using AWS services (Lambda, ECS, etc.).
• Product-Focused Delivery: Go beyond the "how" of the code—bring a product mindset to understand the business logic, user impact, and the "why" behind every feature you build.
• Production Ownership: Troubleshoot and resolve complex production issues in distributed systems, maintaining a "zero-downtime" mentality for our merchants.

What we need:

• Python Mastery: 5+ years of backend engineering experience with deep Python expertise (FastAPI and AsyncIO preferred).
• Polyglot Mindset (Perl): Experience with Perl is a major plus, but a genuine eagerness to learn and work within Perl production code is mandatory. We value engineers who can bridge the gap between legacy and modern systems.
• Distributed Systems Expertise: Proven experience building and scaling microservices architectures and high-throughput systems (e.g., payments, trading, or real-time processing).
• API & Reliability Guru: Deep understanding of integrating third-party APIs, specifically managing webhooks, callbacks, idempotency, and retry policies.
• Cloud & Containers: Strong experience with Docker/Containerization and a solid grasp of AWS cloud infrastructure (Lambda, SQS/SNS, and cloud networking).
• Engineering over "AI Vibe Coding": We value deep engineering logic over blind AI-generated snippets. You should be an advocate for clean, intentional code who can explain the reasoning behind every line you ship.
• High-Load Architecture: Familiarity with event-driven architecture and messaging systems (Kafka, RabbitMQ, etc.).
• Ownership & Mentorship: You have a track record of owning features from design to production and enjoy supporting/mentoring other engineers in the team.
• English Proficiency: Strong English communication skills—both written and verbal—to collaborate effectively across our remote-first, 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

The contract set up type will be assessed subject to your …