Senior Front End Engineer

This role is best suited for a senior-level frontend engineer with 5+ years of experience who enjoys owning frontend architecture and building high-performance, real-time web interfaces using modern frameworks like React, Angular, or Vue. It fits someone comfortable working with complex state, streaming or real-time data, performance optimization, and accessibility in fast-paced, product-driven environments. The position will appeal to engineers who like close collaboration with product, ML, and data teams and want visible impact while scaling user-facing systems.

1. What is your primary frontend tech stack for building high-performance web applications?
   My primary stack is React with TypeScript, modern JavaScript (ES6+), HTML5, and CSS3 (often with CSS Modules or styled-components). I combine this with tools like Vite or Webpack, React Query or SWR for data fetching, and testing frameworks such as Jest and Testing Library.

2. Describe your experience building real-time, data-intensive UIs.
   I’ve built dashboards and trading-style views that consume WebSockets and server-sent events, handling high-frequency updates with efficient diffing, virtualization for large lists, and debounced rendering. I carefully manage subscriptions, batching state updates, and use memoization to ensure smooth performance even under heavy data streams.

3. Which MVC/MVVM frameworks have you used, and which do you prefer for complex SPAs?
   I’ve worked extensively with React, as well as Angular and a bit of Vue. For complex SPAs I prefer React because of its composable component model, mature ecosystem, and flexibility with patterns like hooks, Context, and libraries like Redux or Zustand for state management where needed.

4. How do you approach performance optimization for UIs with frequent state changes?
   I minimize the amount of state and where it lives, split components to reduce re-renders, rely on useMemo/useCallback where appropriate, and use list virtualization for large collections. I also leverage React’s concurrent features, code-splitting, lazy loading, and performance profiling tools to identify and fix bottlenecks in rendering and network usage.

5. Tell me about your experience creating prototypes or wireframes for enterprise workflows.
   I often start by translating product requirements into low-fidelity flow diagrams and simple Figma or Sketch mockups, then build interactive prototypes using Storybook or small sandboxed React apps. For enterprise workflows, I focus on clarity, error states, and edge cases, iterating quickly with stakeholders before committing to full implementation.

6. How do you ensure accessibility and internationalization in your frontend work?
   I follow WCAG guidelines, use semantic HTML, proper ARIA attributes only when necessary, and ensure keyboard navigation and focus management are solid. For internationalization, I rely on libraries like react-intl or i18next, externalize all user-facing copy, support RTL layouts when needed, and test with different locales and languages to catch layout and truncation issues.

7. What is your experience with AWS in the context of frontend applications?
   I’ve integrated frontends with AWS-hosted backends using API Gateway, Lambda, and services behind ALBs, and I’ve worked with CloudFront for CDN and asset caching. I’m comfortable configuring environment variables via SSM/Secrets Manager and using CI/CD pipelines (e.g., GitHub Actions + CodeDeploy) to build and deploy SPAs to S3 + CloudFront.

8. How do you typically collaborate with product and ML/data science teams?
   I partner with product to refine requirements into concrete user flows, and with ML/data science to understand model outputs, latency, and constraints. Together, we design interfaces that expose predictions and insights in a clear, actionable way, often iterating on visualizations and feedback loops so users can trust and act on real-time data.

9. Describe a time you simplified a complex system into a clean, intuitive UI.
   I worked on a complex monitoring tool that exposed dozens of metrics and configuration options. I grouped related actions into guided flows, surfaced only the most critical metrics by default, and moved advanced options into progressive disclosure panels. This reduced user confusion, lowered support tickets, and improved task completion time significantly.

10. Why are you interested in a Senior Front End Engineer role at Jiffy specifically?
    Jiffy’s focus on real-time decision-making in e-commerce and AI aligns perfectly with my background in data-heavy, real-time interfaces. I’m excited about owning front-end architecture in a fast-moving environment, collaborating closely with ML and product teams, and helping define robust UI foundations that scale as Jiffy grows.

This position is a strong match for a senior frontend engineer who wants to own real-time web UI architecture end-to-end—building high-performance React/Angular/Vue interfaces that handle streaming data and frequent state updates, creating enterprise-grade prototypes and workflows with accessible, internationalized HTML/CSS/JavaScript, and collaborating closely with product and ML teams in a fast-paced startup to shape Jiffy’s customer-facing experience, with bonus points if you bring AWS production experience and a background in e-commerce, AI, or image-heavy applications.