This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Staff Backend Software Engineer based in Spain. As a Staff Backend Software Engineer, you’ll help build and evolve a mission-critical transaction platform that enables secure cryptocurrency transfers between financial institutions, fintechs, and exchanges worldwide. You’ll tackle complex distributed systems challenges where data integrity, tenant isolation, reliability, and auditability are essential in a regulated environment. Working primarily with Go and PostgreSQL, you’ll shape core architectural decisions, improve platform scalability, and ensure predictable performance as transaction volumes grow. You’ll also help establish effective engineering practices for AI-assisted development, ensuring generated code meets rigorous production standards. In this remote-first, collaborative environment, you’ll partner with product, compliance, and customer-facing teams while mentoring engineers and taking ownership of the systems you deliver.