Senior Frontend Developer (Next/React)

Greymatter Innovationz; United States; Remote; USD 140,000 - 190,000; Full time

Job summary

Greymatter Innovationz seeks a Senior Frontend Developer to lead design and development of scalable, high-performance web applications using React and Next.js. You will own architecture decisions, mentor junior engineers, and drive frontend best practices while evaluating AI-assisted development tools for quality, security, and performance.

This role emphasizes performance, accessibility, and collaboration with product managers and designers to scope features, estimate effort, and deliver robust

Qualifications

• 5+ years of professional frontend development experience.
• Deep hands-on experience with React and Next.js.
• Strong understanding of state management (Redux/Context/React Query).
• Solid HTML5/CSS3, responsive design, and CSS tooling knowledge.
• Proven performance optimization and Core Web Vitals experience.
• Experience with RESTful APIs and GraphQL, including authentication.
• Hands-on AI coding tools in a real workflow with critical review.
• Strong testing background (Jest/RTL/Cypress/Playwright).
• Proficiency with Git and collaborative workflows.
• Experience with accessibility standards (WCAG/ARIA).
• Excellent communication and stakeholder collaboration.

Responsibilities

• Architect, build, and maintain scalable, production-grade React/Next.js apps.
• Lead design discussions and decisions on component structure and data flow.
• Own performance optimization, bundle size, and rendering strategy.
• Review PRs with focus on quality, accessibility, and security, including AI-generated code.
• Collaborate with backend engineers on REST/GraphQL APIs and error handling.
• Translate design system files into reusable, accessible components.
• Mentor juniors through code reviews and pairing.
• Drive testing strategy (unit/integration/E2E) with Jest, RTL, Cypress, Playwright.
• Partner with product/design to scope features and estimate effort.

Skills

React

Next.js

Architecture

Performance

REST/GraphQL

Testing

AI tools

Git workflows

Accessibility

Mentoring

Education

Bachelor's degree in CS or related field

Tools

Git

Jest

Cypress

Playwright

GraphQL

Job description

Rate: $3,300 USD as contractor (No benefits)

Duration: FTE

Seniority: 6+ years

Experience Required: 6+ years in frontend development, with 3+ years in React and 2+ years in Next.js

About the Role

We are looking for a Senior Frontend Developer to lead the design and development of scalable, high-performance web applications using React and Next.js. You will own architecture decisions, mentor junior engineers, and drive best practices across the frontend codebase. This role also requires comfort using AI-assisted development tools and evaluating AI-generated output for quality, security, and performance.

Key Responsibilities

• Architect, build, and maintain scalable, production-grade applications using React and Next.js (App Router, SSR, SSG, ISR).
• Lead technical design discussions and make architecture decisions for component structure, state management, and data flow.
• Own performance optimization — Core Web Vitals, bundle size, rendering strategy (CSR vs. SSR vs. SSG), and caching.
• Review pull requests with a focus on code quality, scalability, accessibility, and maintainability — including code generated with AI tools.
• Use AI coding assistants (GitHub Copilot, Cursor, Claude, ChatGPT, etc.) to accelerate development, while critically reviewing generated code for correctness, security, and adherence to standards.
• Collaborate with backend engineers to define and consume REST/GraphQL APIs, including error handling and loading states.
• Translate Figma/design system files into reusable, accessible, well-tested components.
• Mentor junior and mid-level developers through code reviews, pairing, and technical guidance.
• Drive adoption of testing strategy (unit, integration, E2E) using tools like Jest, React Testing Library, Cypress, or Playwright.
• Partner with product managers and designers to scope features, estimate effort, and identify technical tradeoffs.
• Stay current with the React/Next.js ecosystem and evaluate new tools, libraries, and AI-assisted workflows for team adoption.

Required Qualifications

• 5+ years of professional frontend development experience.
• Deep, hands-on experience with React (Hooks, Context API, component design patterns) and Next.js (App Router/Pages Router, SSR, SSG, ISR, API routes).
• Strong understanding of state management solutions (Redux, Zustand, React Query/TanStack Query, or similar).
• Solid grasp of HTML5, CSS3, responsive design, and CSS frameworks/tools (Tailwind CSS, Styled Components, or CSS Modules).
• Proven experience optimizing web performance and Core Web Vitals (LCP, CLS, INP).
• Experience with RESTful APIs and/or GraphQL, including authentication (JWT, OAuth).
• Practical, hands-on experience using AI coding tools (Copilot, Cursor, ChatGPT, Claude, etc.) in a real development workflow, with the judgment to review, correct, and validate AI-generated code.
• Strong testing background (Jest, React Testing Library, Cypress, or Playwright).
• Proficiency with Git and collaborative workflows (GitHub/GitLab, code reviews, CI/CD).
• Experience with web accessibility standards (WCAG/ARIA).
• Excellent communication skills, with the ability to explain tradeoffs to both technical and nontechnical stakeholders.

Preferred Qualifications

• Exposure to backend/full-stack development (Node.js) for closer collaboration on API design.
• Experience integrating AI/LLM features into frontend applications (e.g., chat interfaces, streaming responses, prompt-driven UI).
• Experience with cloud/deployment platforms (Vercel, AWS, Azure).
• Prior experience mentoring engineers or leading a small team.
• Bachelor's degree in Computer Science, Engineering, or related field (or equivalent practical experience).

Soft Skills

• Strong ownership mindset and ability to work independently on ambiguous problems.
• Product-oriented thinking — considers the end user, not just the ticket.
• Effective mentor and communicator, comfortable giving and receiving direct feedback.
• Comfortable pushing back on design or product decisions with data-backed reasoning.