Join Colibrix One - Innovating the Future of Payments

At Colibrix One*, we’re building advanced, AI-powered payment technologies that support Payment Service Providers (PSPs), Electronic Money Institutions (EMIs), and neobanks across the EU and the UK. As a fully licensed EMI (FCA reference number 927920) and a Principal Member of Mastercard, we offer real-world financial solutions that include:

• Global card processing
• Digital wallet infrastructure
• Cross-border merchant accounts
• Alternative payment methods (APMs)
• Corporate accounts for legal entities

We’re a fast-growing team with a passion for innovation, security, and scalability. Our culture values curiosity, collaboration, and impact - and we’re looking for talented professionals who are ready to shape the future of fintech.

At Colibrix One, your work directly powers the digital economy. If you're eager to solve meaningful challenges and build with purpose, we’d love to hear from you.

About the role:

We’re building a modern, cloud-native core banking platform focused on resilience, scalability, and regulatory-grade reliability. As a Senior Go Engineer, you’ll design and deliver mission-critical services and features, shape architecture, and mentor the team while we evolve our service-oriented, event-driven system.

Tech stack & environment:

• Languages & APIs: Go (Golang), gRPC, REST
• Cloud & Orchestration: AWS, Kubernetes on Amazon EKS (managed K8s) 
• IaC & Delivery: Terraform (Infrastructure as Code), GitOps with Argo CD 
• Messaging & Streaming: NATS JetStream (durable streams, consumers) 
• Workflows: Temporal (durable, fault-tolerant workflows) 
• Paradigms: Service-oriented architecture (SoA), high availability, horizontal scalability

What you’ll do:

• Design and implement high-throughput, low-latency Go services for core banking domains (accounts, ledgering, payments, reconciliations) following SoA and clean architecture
• Build event-driven components using NATS JetStream (streams, consumers, at-least-once processing) and gRPC/REST APIs for internal and external integrations
• Model long-running, business-critical processes (e.g., settlement, chargebacks) as Temporal workflows/activities for reliability and auditability
• Run everything on EKS with Kubernetes best practices (health/readiness, autoscaling, observability, security)
• Define and manage infrastructure with Terraform; codify environments and promote changes via PRs and automated pipelines
• Operate with GitOps: declarative configs in Git, reconciliation via Argo CD, drift detection, safe rollbacks
• Teamwork & Communication: Be a true team player, fully engaged in daily collaboration. Communicate early and often, share context proactively, and keep teammates aligned

What we’re looking for:

• 5+ years of backend engineering experience, including 3+ years with Go in production. Previous experience in any other backend programming languages is welcome.
• Strong command of concurrency (goroutines, channels), profiling, and performance tuning
• Deep experience designing and operating distributed systems with high availability and fault tolerance
• Hands-on with AWS and Kubernetes (preferably EKS); strong observability and production operations
• Solid understanding of GitOps and experience shipping/operating via Argo CD
• Practical knowledge of event streaming/messaging (ideally NATS JetStream) and API design (gRPC/REST)
• Strong ownership, a bias for automation, and clear, pragmatic communication
• Fluency in both written and spoken English and Russian

Nice to have:

• Proficiency with Terraform and Infrastructure-as-Code workflows (modular code, state management, CI integration)
• Experience with workflow/orchestration platforms (ideally Temporal)
• Banking/fintech fluency: core banking concepts, data integrity, reconciliation, and risk-aware design
• Helm and/or Kustomize for Kubernetes app packaging and config overlays
• Familiarity with consistency patterns (sagas, outbox/inbox, idempotent design) and secure-by-default API practices

Benefits:

• Opportunity to shape the future of fintech solutions within a growing company
• Collaborative, horizontal team structure that values your expertise and ideas
• Chance to work on high-impact projects with internal clients in the banking and financial services sector
• Continuous learning and development opportunities
• Competitive salary and benefits package
• Flexible work arrangements

Salary range:

70 000 - 90 000 EUR gross annually

* Employment will be offered through one of the group’s legal entities - Mellifera Kartiera Ltd, Colibrix Ltd, or Mellifera Operations Ltd - depending on the role, location, and applicable legal framework.

Please note that Colibrix One is a brand representing a group of legal entities. The employment contract will be signed with the relevant company within the group (Mellifera Kartiera Ltd, Colibrix Ltd, or Mellifera Operations Ltd) depending on the nature of the position and jurisdiction

This position is offered within the Colibrix one. Employment will be under the appropriate legal entity based on the role and location.