Staff Software Engineer (Frontend / UI)

Role Description

We are seeking a highly skilled and product-minded Staff Software Engineer to join our team at Function. In this role, you will lead the development of the member-facing experiences that help people understand and act on their health data. You will be responsible for shaping the architecture, performance, and usability of our web and mobile applications while contributing across the full stack.

The ideal candidate is an experienced engineer with deep frontend expertise, strong product instincts, and a passion for building elegant user experiences. You care deeply about performance, usability, accessibility, and design quality, while also being comfortable building APIs, backend services, and scalable systems when needed.

As a key member of our engineering team, you will help define how millions of users interact with their health information and drive technical decisions that shape the future of Function’s products.

Key Responsibilities

• Frontend & Product Development Leadership
  • Lead the architecture, design, and development of modern web and mobile applications.
  • Build intuitive, performant, and highly polished user experiences using React and React Native.
  • Establish frontend best practices around component architecture, state management, testing, accessibility, and performance.
  • Drive the evolution of our design system and shared UI component libraries.
  • Maintain a high bar for product quality, usability, and engineering excellence.
• Full Stack Ownership
  • Own complex features end-to-end, from user interface development through backend services and APIs.
  • Collaborate closely with product, design, and data teams to transform ideas into exceptional customer experiences.
  • Design and implement scalable APIs and services that power our member-facing applications.
  • Contribute to technical decisions across frontend, backend, infrastructure, and data systems.
• User Experience & Performance
  • Champion frontend performance, responsiveness, accessibility, and reliability.
  • Optimize application performance across web and mobile platforms.
  • Leverage analytics and user feedback to continuously improve product experiences.
  • Ensure members can easily understand and interact with complex health information.
• Technical Leadership
  • Provide architectural guidance and technical mentorship across the engineering organization.
  • Lead high-impact initiatives from concept through launch.
  • Drive engineering standards, code quality, and best practices.
  • Help scale engineering processes and systems to support rapid company growth.
• Innovation & Collaboration
  • Partner with Product, Design, Clinical, and Data teams to deliver impactful features.
  • Evaluate emerging technologies and development approaches to improve product quality and team velocity.
  • Foster a culture of continuous improvement, experimentation, and learning.

Qualifications

• 10+ years of software engineering experience, including significant experience building customer-facing products.
• Proven success leading complex technical initiatives in high-growth or startup environments.
• Experience balancing hands-on development with technical leadership and mentorship.
• Deep expertise in JavaScript/TypeScript and modern frontend development.
• Extensive experience with React and modern frontend architectures.
• Strong understanding of design systems, component libraries, state management, accessibility (WCAG), performance optimization, frontend testing frameworks, and modern build and deployment tooling.
• Experience building highly interactive, data-rich user interfaces.
• Understanding of mobile architecture, performance optimization, and platform-specific considerations.
• Experience designing and building APIs and backend services.
• Strong proficiency with Python or similar backend technologies.
• Ability to comfortably work across the entire application stack.
• Experience integrating third-party services and external data platforms.
• Strong product instincts and a passion for creating exceptional user experiences.
• Ability to balance technical excellence with business impact.
• Experience collaborating closely with Product and Design teams.
• Strong understanding of Agile development methodologies, test-driven development, continuous integration and deployment, software architecture principles, and scalable system design.
• Commitment to writing maintainable, high-quality code.

Requirements

• Ability to make progress in ambiguous environments.
• Strong ownership mentality and willingness to tackle difficult problems.
• Comfortable making decisions with incomplete information.
• Adaptable and resourceful in fast-moving environments.
• Excited to build processes, systems, and products from the ground up.
• Thrives in rapidly evolving business and technical landscapes.
• Exceptional communication skills.
• Ability to explain complex technical concepts to non-technical stakeholders.
• Strong collaborator across Engineering, Product, Design, and Operations teams.
• Passion for learning new technologies and approaches.
• Willingness to challenge assumptions and improve existing systems.
• Growth mindset focused on continuous improvement.

Benefits

• Competitive salary and benefits package.
• Flexible working hours.
• Dynamic work environment where creativity and innovation are encouraged.