Senior Full-Stack Engineer (React/Node.js)

Location: Erevan, Armenia; Canberra, Australia; Vienna, Austria; Brussells, Belgium; Sarajevo, Bosnia and Herzegovina; Sofia, Bulgaria; Zagreb, Croatia; Prague, Czechia; Berlin, Germany; Athens, Greece; Rome, Italy; Dublin, Ireland; Kishinev, Moldova, Republic of; Budva, Montenegro; Bucharest, Romania; Tbilisi, Georgia; Warsaw, Poland; Bratislava, Slovakia; Astana, Kazakhstan; Beograd, Serbia Workplace: remote Senior Full-Stack Engineer About the Role We are looking for Senior Full-Stack Engineer with strong experience across React/TypeScript frontend development and Node.js/TypeScript backend systems. This is a long-term, fully remote opportunity within a fast-moving fintech environment, working EST hours. The ideal candidate is proactive, asks thoughtful questions, and builds reliable, maintainable systems. The team actively uses AI coding tools such as Claude, so candidates must be comfortable using them and explaining their technical decisions. Responsibilities Build and maintain production-grade React, Node.js , and TypeScript applications. Develop backend services, APIs, integrations, and server-side validation. Manage PostgreSQL schemas, migrations, queries, indexes, and performance. Write unit, integration, and end-to-end tests. Design scalable systems using caching, queues, and background jobs. Improve legacy code and contribute to ongoing technical remediation. Collaborate with the team and clearly communicate technical decisions. 7+ years of professional software engineering experience. Strong, recent React, Node.js, and TypeScript experience. True full-stack expertise; primarily frontend candidates will not be considered. Hands-on PostgreSQL experience, including migrations and indexing. Production experience with AWS; ECS/Fargate, containers, S3, and CloudFront are preferred. Experience with system design, third-party integrations, and end-to-end testing. Comfortable using AI coding tools such as Claude. Strong English and Russian communication skills. Fintech or payments experience is preferred, including knowledge of ACH, reconciliation, compliance, and idempotency.