AI-Native Fullstack Engineer (Go + React)

Colibrix One develops cutting-edge IT solutions for Payment Service Providers (PSPs), Electronic Money Institutions (EMIs), and neobanking platforms across the European Union and the UK. Their mission is to create secure, scalable, and high-performance payment technologies that fuel financial innovation and empower businesses in the digital economy.

• 3–5 years of professional software engineering experience
• Strong Go backend engineering skills including services, APIs, concurrency, and data consistency with knowledge of MongoDB, NATS, and gRPC
• Experience with event-driven architecture, message brokers (preferably NATS), idempotent consumers, outbox patterns, sagas/compensations, retries with DLQ, and eventual consistency
• Working knowledge of React and TypeScript to deliver and review SPA features
• Payments/fintech experience is a strong plus, especially related to idempotency, transactional integrity, money handling, audit trails, subscriptions, and recurring billing
• Proven ability to read, debug, and refactor unfamiliar code
• Hands-on production experience with AI coding agents
• Discipline to maintain traceability from requirements to code and tests

• Take a spec and drive it to production by clarifying ambiguities, decomposing work into verifiable increments, and executing tasks via AI agents
• Design verification before generation including acceptance criteria, tests, invariants, and API contracts
• Review and accept agent-generated code to identify issues such as scope creep and hallucinated APIs
• Step in and write code manually when AI agents reach dead ends, mainly in Go
• Build and tune the agent toolchain including skills, prompts, guardrails, and workflows, and measure key metrics like first-pass acceptance rate and cycle time

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