Senior Fullstack Engineer

At Koalafi, we believe in a world where no one has to put an important purchase on hold. That’s why we’re making it easier for more people to pay for big purchases over time.

Retailers across the country rely on us to offer flexible lease‑to‑own financing to their non‑prime consumers, while increasing sales and strengthening customer loyalty. Their 2M+ customers love us because we provide a flexible way for them to make payments and give them an opportunity to improve their credit. Our 200+ Koalafi teammates enjoy inspiring and challenging work that accelerates their careers.

Interested in learning more about how we’re transforming the financing experience and joining our team?

Are you ready to lead the transformation of mission‑critical financial systems? We’re seeking a talented engineer to join Koalafi and lead our newly formed Customer Servicing SWAT team. You’ll be at the forefront of modernizing our core lease servicing platform, extracting critical business logic from legacy systems while building the foundation for our next‑generation servicing architecture.

In this role, you'll help architect and deliver modern microservices that handle high‑volume daily payment processing, lease management, and customer servicing operations by decomposing our legacy .NET monolith into scalable, maintainable services using Golang, AWS serverless, and React. You'll work with both legacy C#/.NET systems and modern cloud‑native architectures, creating the bridge between our current state and future vision.

• Legacy System Decomposition: Analyze, understand, and extract critical business logic from our C#/.NET monolith, designing modern microservices using Golang that maintain operational excellence during migration.
• Architect Modern Services: Design and build new payment processing, lease management, and servicing APIs that serve as the foundation for next‑generation servicing capabilities and automated customer support.
• Build Bridge Architecture: Create backend‑agnostic servicing interfaces and APIs that can seamlessly operate with both legacy systems and new services, enabling gradual migration without business disruption.
• Ensure Payment System Reliability: Modernize and stabilize critical batch processing jobs that handle daily payment collection, ensuring high uptime for systems processing significant daily transaction volumes.
• Enable Business Capabilities: Extract and modernize business logic to support new features like flexible promotional schedules, automated agent integration, and item‑level tax calculations that drive significant revenue opportunities.
• Implement Observability: Design robust monitoring, alerting, and observability frameworks for payment processing and lease servicing operations to ensure high availability and rapid issue resolution.
• Cross‑System Integration: Work with Shared Tech and other product teams to integrate with event streaming, communications platforms, and shared services while maintaining backwards compatibility.
• Risk Management: Lead incident response for payment processing systems and implement preventative measures to protect revenue‑critical operations during modernization efforts.

• 4+ years of professional experience in systems development with experience modernizing or migrating legacy systems in production environments.
• Proficiency in Golang: Strong experience developing backend services, APIs, and financial systems using Golang in production environments.
• Legacy System
  
  Experience:
  
  Ability to read, understand, and analyze C#/.NET codebases to extract business logic and identify service boundaries in complex monoliths.
• React/Type Script
  
  Experience:
  
  Experience building frontend applications and customer‑facing interfaces using React and Type Script.
• Cloud
  
  Experience:
  
  Strong familiarity with AWS services and cloud‑native architectures, with experience in containerization and modern deployment practices.
• Strong Testing Practices: Experience with automated testing strategies for both legacy system integration and new service development, including contract testing and data validation.
• Migration Expertise: Experience with gradual system migrations,…