Middle (aspring Senior) Software Development Engineer

Financial Gateway Backend Engineer

The Financial Gateway team builds the core platform responsible for delivering accurate, transparent, and timely financial data to internal stakeholders and external clients.

We operate at the heart of the company's financial ecosystem, designing reliable data pipelines, billing calculation engines, and financial data services that power billing systems, FP&A, intercompany flows, and reporting processes.

Our mission is to ensure financial data is: Correct, Traceable, Scalable, and Consistently available across systems.

This is a data-intensive, architecture-driven backend role focused on financial correctness, integrations, and system reliability — not UI or feature CRUD development.

What You Will Work On:

You will design and develop systems that:

• Collect and store raw financial data from products and partners
• Manage contract data and currency rates for billing calculations
• Perform billing calculations with full transparency and traceability
• Validate, monitor, and control financial data pipelines
• Export billing results to billing and financial systems (FP&A, intercompany, reporting, etc.)
• Integrate multiple internal and external services
• Improve system performance, reliability, and data correctness
• Work across split infrastructures (ex-IPONWEB and CRTO environments)

Your Responsibilities:

• Deliver high-quality features on time
• Design scalable solutions considering long-term usage
• Participate in design and code reviews
• Write clear technical specifications when needed
• Troubleshoot complex data and system issues
• Monitor performance and reliability of services
• Write automated tests (unit, functional, integration)
• Work independently and take ownership of problems
• Collaborate with multiple projects and stakeholders

What We're Looking For:

This role is ideal for a backend engineer with a strong data and systems mindset, especially someone experienced with financial, billing, reporting, or integration-heavy systems.

Required Skills:

• 3+ years of backend development experience
• Strong Python 3 knowledge (core concepts and internals)
• Experience building REST APIs with Django / DRF
• Solid experience with PostgreSQL and SQL query optimization
• Understanding of data structures, algorithms, and complexity
• Good understanding of HTTP and networking basics
• Experience designing features, writing documentation, and providing estimations
• Experience with CI/CD and automation processes
• Comfortable working with Unix systems
• Knowledge of OOP, SOLID principles, and design patterns
• Passion for writing maintainable tests
• Strong problem-solving skills and ability to work independently
• Good written English (Russian is a plus)

Nice to Have (Strong Plus):

• Experience in fintech, billing, payments, reporting, or data platforms
• Experience working with data validation, reconciliation, and monitoring
• Experience integrating with external partners/services
• Experience debugging production data issues across services

Why This Role Is Interesting:

You will not be building simple APIs. You will be building the financial backbone that other systems rely on.

This role gives you exposure to:

• Financial data architecture
• Data correctness and reconciliation challenges
• Complex integrations
• High-impact backend systems
• Cross-team and cross-system engineering

Who Will Succeed Here? Engineers who:

• Care about data correctness and system reliability
• Enjoy debugging complex data flows
• Think in terms of architecture, not just endpoints
• Take ownership and work independently
• Like solving real, non-trivial backend problems

What you'll love about us:

• Independence and freedom to take initiative
• Authenticity and transparency
• Clear, achievable goals
• Driven people who are passionate about what they do
• A skilled team, eager to share their knowledge and learn from you
• A focus on quality over quantity in everything we do

About us:

We're MARGO. Founded in Paris in 2005, we've since expanded to two more capitals - London and Warsaw. We specialize in IT outsourcing, focusing on complex, cutting-edge IT projects. Our success is fueled by strong relationships with ambitious, visionary clients who are dedicated to innovation and progress.

At MARGO, we believe in people. That's why we empower our team members with substantial responsibility, the freedom to take initiative, and endless opportunities for growth. Here, everyone p