Sr. Fullstack Engineer

About Tereina Tereina is on a mission to revolutionize B2B payments. We are a well-funded, early-stage  startup building cutting-edge solutions that transform how businesses move money. Our  platform handles cross-border payment processing, counterparty management, bank account  administration, and compliance workflows for eterprise customers worldwide. We are building a modern portal application using a service-oriented architecture with Spring  Boot microservices, a Spring Boot BFF (Backend for Frontend), and a custom frontend built with  SAP UI5 Web Components, React and TypeScript. We are currently evolving our UX with a  clean, data-rich design language focused on advanced search, tabular data views, and  dashboard analytics. About the Role As a Senior Fullstack Engineer, you will be a key technical leader responsible for shaping the  user experience of the Tereina Portal. You will own the frontend architecture, drive the  implementation of our new design system, and work across the full stack to ensure our UX  vision is realized with production-quality code. You will partner closely with product, design, and  backend engineers to deliver enterprise-grade interfaces for payment operations, counterparty  management, and compliance with workflows. This role demands deep expertise in modern frontend technologies, a strong eye for design  quality, and the ability to influence architecture decisions across the portal and its supporting  BFF layer. You will mentor other engineers on UX best practices and help define our standards  for accessibility, performance, and component reusability. Key Responsibilities Framework Development These are the responsibilities focused on building the underlying systems, architecture, and  shared infrastructure: Frontend Architecture: Own and evolve the frontend architecture of the Tereina Portal,  including the component library, state management patterns, and data-fetching layer  built on our existing frontend infrastructure. Design System Implementation: Lead the implementation of our evolving design system,  translating UX designs into reusable, accessible components using SAP UI5 Web  Components and TypeScript. Establish patterns for dashboards, data tables, search  interfaces, and detail views. BFF Collaboration: Work closely with the BFF layer (Spring Boot) to shape API  contracts, optimize data-fetching patterns, and ensure the portal proxy controllers deliver  exactly what the frontend needs. Influence the design of search proxy endpoints and  OpenAPI specifications. Performance & Accessibility: Champion frontend performance optimization (lazy loading,  caching strategies, efficient re-renders) and WCAG accessibility standards across all  portal views. Rollout & Adoption These are the responsibilities focused on shipping features, driving usage, and working across  teams: Search & Data Views: Architect the frontend implementation of our new standardized  search…