Senior Fullstack Engineer, Sage

• This role is ideal for someone who thrives on solving complex user-facing problems, has strong opinions about frontend architecture and APIs, and wants to own the end-to-end delivery of new capabilities
• We expect candidates will typically have at least 5+ years of full-stack engineering experience, with a track record of leading complex projects at scale
• Deep understanding of core React concepts (virtual DOM, componentization, component lifecycle, hooks) and advanced proficiency with building complex frontends using those concepts
• Expertise with TypeScript and modern JavaScript (ES6+)
• Principled approach to managing application state, knowing how to leverage local, contextual, and global state management options
• Well-reasoned opinions on route architecture and use of routing concepts (e.g. dynamic and nested routes, route guards, programmatic navigations)
• Experience with PWA technologies (service workers, offline caching, push notifications, responsive design)
• Working knowledge of backend technologies (Java, Node.js, or similar)
• Experience designing and consuming RESTful and/or GraphQL APIs
• Comfort with relational and/or NoSQL databases
• Hands-on experience implementing OAuth2, OIDC, JWT, and related authentication/authorization patterns
• Understanding of secure web application practices (CSRF, XSS, CORS, etc.)
• Strong understanding of how to design applications that scale
• Knowledge of caching strategies, asynchronous data flows, and client-server performance tradeoffs
• Experience with build systems and bundlers (Webpack, Vite, etc.)
• Familiarity with CI/CD pipelines and modern deployment environments
• Ability to lead design reviews and technical discussions
• Track record of mentoring peers and setting engineering standards
• Strong communication skills with both technical and non-technical stakeholders

Desirable

• We’re looking for an experienced Full-Stack Engineer to serve as a senior IC on a new, high-impact project
• While you’ll bring solid backend experience, your strength and passion will be on the frontend building scalable, performant web applications in the modern React ecosystem
• You’ll take ownership of the application architecture and help define the design patterns, frameworks, and best practices that shape how we build software going forward
• You’ll be hands-on, collaborative, and deeply influential in setting technical direction while ensuring that our applications are robust, secure, supportable, and optimized for scale
• Lead Development: Architect and implement complex frontend systems in React, while contributing to backend services as needed
• Define Standards: Establish design patterns, frameworks, and best practices for building scalable, maintainable web applications
• Own Authentication & Security: Design and integrate secure authentication/authorization flows (OAuth2, OIDC, JWT) into user-facing applications
• Collaborate Across Stack: Work with backend and infrastructure engineers to design and optimize APIs, data flows, and integration points
• Optimize for Performance: Improve rendering performance, load times, caching, and responsiveness across devices and network conditions
• Mentor & Guide: Provide technical leadership, code reviews, and mentorship to other engineers
• Shape the Future: Play a central role in defining the technical trajectory of a new, mission-critical product