Senior Backend Developer

Job Description

Shape the Future of Payments with Nexi in 2026

Envision a world where every transaction feels effortless, safe, and connected. At Nets as a part of Nexi we’re leading this transformation, building tools and solutions that redefine how the world pays. By joining us, you’ll play a part in creating the next generation of digital payments in an innovative, supportive, and international environment.

Why This Role Is Right for You

As a Senior Backend Developer you’ll join a collaborative and forward-thinking international team. Together, we work on reimagining how ISVs onboard and integrate payment services .

You’ll be at the core of a strategic program to launch a low-code, modular partner platform that radically accelerates merchant onboarding. Our architecture leverages micro front-end (MFE) and self-contained systems (SCS) to offer seamless, embeddable payment experiences within partner software.

This is more than a technology project — it’s a foundational shift in how Nexi collaborates with external developers and platforms across Europe. As a Backend Technical Specialist, you will help define and shape an ecosystem of modular services that prioritize speed, flexibility, and developer autonomy while ensuring security and compliance.

About Your Future Role

In this position, you will:

• Design and take part of the implementation of a scalable backend architecture based on Self-Contained Systems (SCS)
• Define and enforce backend design principles including domain-driven design, API standards, and database strategies
• Decompose platform functionality into independent vertical services (e.g. Merchant Onboarding, Partner Management, Terminal Management)
• Be part of the development team in delivering secure, performant services that handle onboarding flows, merchant creation, and third-party system integration
• Take part to the service-to-service communication, data propagation to downstream systems, and connectivity with legacy platforms (e.g. TMO, CRM)
• Collaborate with frontend and DevOps teams to align APIs with frontend needs and to define robust, cloud-native infrastructure setups
• Ensure high availability, reliability, and observability of backend services to support real-time partner operations and reduce support burden
• Work in a hybrid working model in Helsinki Metropolitan Area
  
  

What Makes You a Great Fit

We’re looking for someone eager to make a difference. Here’s what we value:

Essential Qualifications:

• Proven experience as a backend architect or developer in distributed systems or microservice-based platforms
• Strong expertise in designing and deploying Self-Contained Systems or similar decoupled backend architectures
• Solid understanding of API-first development, domain-driven design, and secure handling of sensitive data
• Experience with integration of backend services to third-party systems and legacy infrastructure
• Fluency in Java and Kotlin and familiarity with cloud-native stacks (AWS, Azure, Kubernetes)
  
  

Bonus Skills:

• Familiarity with onboarding, KYC or merchant management processes in fintech or banking
• Experience with event-driven architectures (e.g. Kafka, Pub/Sub)
• Hands-on DevOps knowledge (CI/CD pipelines, monitoring, container orchestration)
• Exposure to compliance-sensitive environments (PCI DSS, GDPR, etc.)
  
  

Even if you don’t check every box, your unique potential and willingness to learn could set you apart.

What’s in it for You ?

• Attractive salary and a competitive benefits package to reward your expertise and contributions
• Tech equipment: Get the tools you need to succeed, including the latest technology to support your work
• Join an international team: Collaborate with experts from across Europe and bring your ideas to life in a dynamic, global environment
• Grow and develop: Gain hands-on experience and structured training through our PayTech University , designed to accelerate your career and help you reach your full potential
  
  

About The Recruitment Process

Due to the work related to critical payment technology, the selected candidate will undergo a basic level security clearance.

Ready to Join Us?

Apply directly via our careers page and send us your CV and application letter by Tuesday 31 st of March 2026. We’d love to hear how you’d help shape the future of payments.

Responsibilities

QUALIFICATIONS