Senior Frontend Engineer

Merciv•New York, NY

3d•$150,000 - $200,000

About The Position

Merciv is transforming how brands understand consumers through autonomous AI that doesn’t just analyze data — it proactively surfaces insights that drive million-dollar decisions. Our platform powers some of the largest retail and consumer goods organizations in the world, synthesizing signals from thousands of sources to reveal patterns and opportunities before competitors see them coming. As we scale our enterprise platform and launch our self-serve tier, we need a Senior Frontend Engineer who can craft exceptional user experiences that make complex AI-powered insights feel intuitive and actionable. This is your chance to build the interface that puts autonomous consumer intelligence into the hands of brand leaders, researchers, and marketers. You’ll own critical parts of our frontend architecture, building the UI that enables users to explore millions of data points, understand nuanced consumer sentiment, and make confident decisions backed by AI reasoning. Working closely with our product, design, and AI teams, you’ll create elegant experiences that transform dense analytical outputs into clear, compelling narratives. This is a hands-on role where you’ll build the interactive components that enterprise brands rely on daily to stay ahead of market shifts. In this role, you’ll be the architect of experiences that must be enterprise-grade (fast, accessible, secure) while maintaining startup agility. Your work directly impacts whether a brand leader can understand a critical consumer trend in seconds or gets lost in data — a difference measured in millions of dollars of opportunity.

Requirements

6-10+ years of professional frontend development experience
4+ years building complex, production web applications with modern JavaScript frameworks
2+ years with React in production environments
Experience working in fast-paced startup or high-growth product environments
Track record of owning significant frontend features end-to-end
Expert-level knowledge of HTML5, CSS3, and modern JavaScript (ES6+)
Deep understanding of TypeScript and type-safe development practices
Strong command of responsive design principles and cross-browser compatibility
Expertise in web performance optimization techniques (lazy loading, code splitting, caching)
Advanced React proficiency including hooks, context, and component lifecycle
Experience with state management solutions (Redux, Zustand, or similar)
Knowledge of React ecosystem tools (React Router, React Query, etc.)
Understanding of React performance optimization and rendering patterns
Strong expertise in modern CSS approaches (CSS Modules, Styled Components, Tailwind, or similar)
Proficient with build tools and bundlers (Vite, Webpack, or similar)
Experience with version control (Git) and collaborative development workflows
Familiarity with CI/CD pipelines and automated testing frameworks
Experience integrating RESTful APIs and GraphQL endpoints
Understanding of asynchronous JavaScript and promise-based workflows
Ability to handle complex data transformations and state management
Experience with WebSocket or real-time data streaming
Proficiency with testing frameworks (Jest, React Testing Library, Cypress, or similar)
Experience writing unit, integration, and end-to-end tests
Understanding of test-driven development practices
Strong debugging skills across browsers and devices
Experience building interactive data visualizations (D3.js, Recharts, Chart.js, or similar)
Ability to translate complex datasets into clear, compelling visual stories
Understanding of visualization best practices and accessibility
Track record of taking full ownership of features and seeing them through to successful production deployment
Strong product sense with ability to balance technical constraints with user needs and business objectives
Excellent written and verbal communication skills; comfortable explaining technical concepts to non-technical stakeholders
Thrives in cross-functional environments, working closely with designers, product managers, and backend engineers
Obsessive attention to detail in implementation, from pixel-perfect designs to edge case handling
Passionate about building experiences that users love; consistently thinks from the user’s perspective
Ability to balance immediate feature delivery with long-term architectural decisions
Continuous learner who stays current with frontend technologies and best practices; eager to experiment with new tools
Strong debugging and problem-solving skills; comfortable working through ambiguous requirements
Committed to writing clean, maintainable, well-documented code that your teammates will thank you for

Nice To Haves

Experience building data-intensive or analytics-focused applications
Familiarity with AI/ML user interfaces or conversational UI patterns
Background in design systems and component library development
Experience with Next.js or other React meta-frameworks
Knowledge of backend technologies (Node.js, Python) for better full-stack collaboration
Experience with Figma or other design tools for design-development collaboration
Familiarity with accessibility best practices and ARIA standards
Experience with micro-frontend architectures or module federation
Understanding of WebGL or advanced graphics for data visualization
Background in consumer research, market intelligence, or retail/CPG domains
Experience with A/B testing frameworks and feature flag systems
Knowledge of web analytics and user behavior tracking
Experience scaling frontend applications from early-stage to enterprise

Responsibilities

Build Exceptional User Experiences: Design and implement elegant, high-performance React components that make complex AI insights feel simple and actionable
Architect for Scale: Own critical parts of our frontend architecture as we grow from hundreds to thousands of daily active users across Fortune 500 enterprises
Collaborate Cross-Functionally: Partner with product managers, designers, and AI engineers to translate sophisticated analytical outputs into intuitive visualizations and workflows
Drive Frontend Excellence: Establish coding standards, conduct rigorous code reviews, and mentor team members on modern frontend best practices
Optimize Performance: Ensure sub-second load times and smooth interactions even when rendering complex data visualizations and real-time updates
Champion User-Centric Design: Work closely with UX/UI designers to implement pixel-perfect designs while advocating for usability and accessibility
Own Feature Development: Take features from concept to production, including requirements gathering, technical design, implementation, testing, and deployment
Enable AI Interaction: Build innovative interfaces for users to interact with agentic AI systems, including natural language inputs, conversational flows, and transparent reasoning displays
Ensure Quality & Reliability: Write comprehensive tests, debug across browsers and devices, and maintain high code quality standards for enterprise customers
Shape Product Direction: Contribute to product strategy discussions, bringing frontend expertise to inform what we build and how we build it