This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Ruby Developer (Ruby & Go) based in Canada. This is a senior backend engineering opportunity focused on building and scaling secure, reliable payment infrastructure for a global fintech environment. You will take ownership of the backend powering payment portals and integrations with payment service providers. The role combines Ruby on Rails expertise with Go development for high-throughput and latency-sensitive services. You will design end-to-end deposit and withdrawal flows while ensuring robust transaction processing, reconciliation, and failure handling. Security and reliability are central, with a strong focus on financial data protection and compliance. You will also contribute to technical direction, mentor engineers, and help evolve a high-performing international engineering environment.