Sr Software Engineer - UI

Role Overview 
 
We're looking for a talented Frontend Engineer who leads with UI but isn't afraid to go deep. You thrive in a fast moving environment, ship polished interfaces with TypeScript and React and embrace AI-assisted development as a core part of your workflow. This role is front-end-first, but the expectation is that you'll grow into full stack ownership over time. 

How You Contribute 

• Design and build responsive, performant UIs using React, TanStack, Zustand, TypeScript and/or JavaScript 

• Collaborate on feature development end-to-end, gradually taking on backend work as you grow 

• Use GitLab for version control, CI/CD pipelines, merge request workflows, and issue tracking 

• Deploy and manage workloads on Google Cloud Platform CDN, working alongside with services like GKE, and Cloud Storage 

• Leverage AI-assisted (vibe coding) tools to accelerate development — you're comfortable using Copilot, Cursor, Claude, or similar tools as a force multiplier 

• Write clean, maintainable code with strong typing and component reuse in mind 

• Partner closely with designers and product to translate specs into real, shippable experiences 

• Participate in code reviews, retrospectives, and architectural discussions 

 

Required Skills and Qualifications  

• 5+ years of + post-internship experience with React and TypeScript. 

• Solid JavaScript/ TypeScript, HTML, CSS  

• Knowledge of UI Component Libraries, Web Accessibility, Internationalization  

• Ability to work with test libraries (Jest, Playwright)  

• Proficient in React, TanStack, Zustand  

• Engineering focus  

• Overall system knowledge   

• Working knowledge of Jira, GitLab, Visual Studio, CI/CD  

• Proficient in Google Cloud Platform, Kubernetes, BigQuery, Cloud SQL, CDN  

• Ability to use Claude Code 

Desirable Qualifications 

• AI Tools 

• Micro Front End Architecture 

• Java/ Springboot 

• Database SQL/ NoSQL 

Five9 embraces diversity and is committed to building a team that represents a variety of backgrounds, perspectives, and skills.  The more inclusive we are, the better we are.  Five9 is an equal opportunity employer.  

This role is hybrid and requires 3 days a week in office.