Senior Go Engineer (Core Banking)

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 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. The ideal candidate will bring deep technical expertise, a collaborative mindset, and the ability to influence and mentor team members through knowledge and experience rather than formal authority. What You Need to Succeed 5+ years of professional Go development experience, including 3+ years in fintech, banking, payments, or other transaction-critical systems Strong knowledge of distributed systems, microservices, and API design (REST and gRPC) Advanced PostgreSQL skills, including transactions, isolation levels, locking, indexing, migrations, and concurrency Experience designing reliable transactional systems using idempotency, retries, event deduplication, transactional outbox, sagas, and reconciliation Hands-on experience with event-driven architectures and message brokers such as NATS, Kafka, or RabbitMQ Experience building and operating production services, including incident investigation, safe deployments, database migrations, and observability Practical knowledge of AWS, Kubernetes, and CI/CD Experience integrating with banks, payment providers, processors, AML/KYC, or anti-fraud platforms Understanding of security requirements for financial and personal data Ability to translate business requirements into technical solutions and independently drive implementation Strong communication skills and working proficiency in Russian and English Banking Domain Experience Hands-on experience in several of the following areas is highly valued: Ledgers, accounting flows, accounts, and balance management Holds, reversals, adjustments, reconciliation, and settlement SEPA, SWIFT, and ISO 20022 Card transaction lifecycles and card scheme integrations Nice to Have Experience with Temporal or a similar workflow engine Experience with NATS/JetStream, GitLab CI/CD, OpenTelemetry, Prometheus, Grafana, Loki, or Tempo Knowledge of event sourcing or append-only financial data models Familiarity with PCI DSS…