Senior Go Engineer (Colibrix Partners)

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 Electronic Money Institution (FCA Reference No. 927920) and holder of a Financial Institution Licence issued by the MFSA, as well as a principal member of both VISA and Mastercard, we provide comprehensive, real-world financial solutions that include: Global card processingDigital wallet infrastructureCross-border merchant accountsAlternative 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. Tech stack: Go, MongoDB, Redis, NATS, JetStream, REST/gRPC, AWS, Kubernetes, GitLab CI/CD, ArgoCD, Prometheus, Grafana. Key responsibilities: Design and develop Go-based services for the Colibrix Partners card-issuing platform — card lifecycle (issuance, top-ups, blocks, replacement, expiry), wallets and balances, fees and commissions, authorisation and clearing flows — with a focus on stability, fault tolerance, and correct handling of financial operationsTranslate business requirements into clear technical specifications and propose concrete solutions at the service and module level, including API design, data models, and integrations with external providersBuild solutions in compliance with security requirements, including PCI DSS, proper handling of sensitive data, and secure inter-service communicationAnalyze and optimize service performance, including code profiling, concurrency handling, and efficiency of data storage and network interactionsParticipate in the architecture of microservices: service boundaries, communication patterns, load balancing, error handling, queues/streaming, and data storage approachesProduce maintainable, testable code with appropriate unit and integration test coverage, following team development standardsParticipate in code review as part of the development process: evaluate implementations, identify issues, and provide constructive feedback aligned with technical requirementsContribute to technical discussions by offering concrete, practical solutions within the current architecture and development processes What You Need to Succeed in This Role: 3-5 years of Go development experience focused on backend systems, and around 3 years of experience working with fintech applicationsUnderstanding of distributed systems, microservices architecture, and API design, including REST/RPC transportsExperience working with SQL and NoSQL databases, message brokers (Kafka, NATS), and caching systemsFamiliarity with CI/CD practices and tools, preferably GitLabExperience working with the AWS cloud platformAbility to contribute expertise and collaborate with the team on technical solutionsStrong communication skills and the ability to explain complex technical ideas to colleagues with varying levels of technical backgroundFluency in written and spoken English and RussianExperience in the fintech domainSecurity-by-design mindset: ability to design solutions with security considerations built in at every stageUnderstanding of regulatory requirements in the fintech space (e.g., PCI DSS, GDPR)Experience in performance optimization and building high-availability systemsExperience with observability tools: logging, metrics, tracing (Prometheus, Grafana, OpenTelemetry) What We Offer: Opportunity to shape the future of fintech solutions within a growing companyCollaborative, horizontal team structure that values your expertise and ideasContinuous learning and development opportunities to enhance your skills and career growthCompetitive salary and benefits packageFlexible work arrangements to support work-life balance This position is offered within the COLIBRIX ONE. Employment will be under the appropriate legal entity based on the role and location