Frontend Developer Jobs in Chelsea, MA (NOW HIRING)

Job Summary:
Blitzy is a Cambridge, MA based AI software development platform on a mission to revolutionize the software development life cycle. They are seeking a Senior Frontend Engineer to lead frontend engineering efforts, architect sophisticated interfaces, mentor junior engineers, and establish best practices as the company scales.
Responsibilities:
• You architect and implement sophisticated frontend solutions that handle complex state management, real-time AI agent updates, and intuitive developer workflows.
• You establish frontend engineering standards, patterns, and best practices that scale with our growing team.
• You build responsive, performant interfaces that work seamlessly across browsers and devices while maintaining sub-second interaction speeds.
• You refactor and modernize existing frontend code, eliminating technical debt while shipping new features.
• You make architectural decisions that balance immediate product needs with long-term scalability and maintainability.
• You mentor junior frontend engineers, conducting code reviews and elevating the team’s technical capabilities.
• You collaborate closely with product, design, and backend teams to deliver cohesive user experiences.
• You evaluate and introduce new technologies and frameworks that improve our development velocity and product quality.
• You maintain high standards for code quality, performance, testing, and accessibility.
• You become a trusted technical advisor to leadership on all frontend architecture decisions.
• As our Senior Frontend Engineer and technical lead, you’ll own:
• Frontend architecture and technical decision-making for our core platform.
• Refactoring existing frontend systems to improve performance and maintainability.
• Building new platform features that showcase our AI capabilities to enterprise users.
• Establishing component library and design system foundations.
• Setting up testing frameworks and CI/CD pipelines for frontend.
• Code review processes and engineering standards.
• Growing Responsibilities:
• Mentoring and providing technical guidance to junior frontend engineers.
• Performance optimization and monitoring systems.
• Frontend infrastructure and build tooling improvements.
• Cross-team collaboration on API design and integration patterns.
• Technical documentation and onboarding processes.
• Long-term Vision:
• Scaling the frontend engineering team and practices.
• Defining frontend engineering hiring standards and interview processes.
• Contributing to product and technical strategy discussions.
• Building advanced features like real-time collaboration, AI-powered UIs, and developer tools.
Qualifications:
Required:
• 10+ years of frontend development experience with a proven track record of building complex, production-grade applications.
• Expert-level knowledge of modern JavaScript/TypeScript with deep understanding of language features, patterns, and best practices.
• Deep expertise in React.js and its ecosystem including hooks, context, performance optimization, and modern patterns.
• Strong understanding of state management (Redux, MobX, Zustand, or similar) and when to apply different patterns.
• Experience with modern build tools (Webpack, Vite, esbuild, etc.) and their configuration.
• Proven ability to architect scalable frontend systems that handle complexity while remaining maintainable.
• Experience with responsive design and cross-browser compatibility, ensuring consistent experiences across devices.
• Strong understanding of web performance optimization including bundle size, rendering performance, and Core Web Vitals.
• Experience with frontend testing frameworks and methodologies (Jest, React Testing Library, Playwright, Cypress).
• Track record of technical leadership including mentoring, code reviews, and establishing engineering standards.
Preferred:
• Experience with GraphQL and real-time data handling (WebSockets, Server-Sent Events).
• Knowledge of WebAssembly and its applications in frontend development.
• Experience with micro-frontend architectures or monorepo management.
• Contributions to open-source projects, especially in the React or JavaScript ecosystem.
• Experience with advanced animations and complex UI interactions (Framer Motion, React Spring).
• Deep knowledge of accessibility standards (WCAG) and practical implementation.
• Experience with design systems at scale and component library architecture.
• Speaking engagements or technical writing demonstrating thought leadership.
• Experience at high-growth startups or in technical leadership roles.
• Experience working effectively with AI coding tools (Blitzy, Copilot, Cursor, Claude, etc.) to accelerate frontend development without compromising code quality or engineering standards.
• Proven ability to review and validate AI-generated code—identifying subtle logic errors, security gaps, and style inconsistencies that automated tools routinely miss.
• Track record of writing precise, reusable prompts for frontend tasks including component generation, test writing, refactoring, and PR documentation to get consistent, production-ready output.
• Experience establishing team-wide processes for AI-assisted development—defining when to use AI, how to review its output, and how to integrate it cleanly into existing PR and code review workflows.
Company:
Blitzy is a Generative AI software platform that aims to automate custom software development. Founded in 2023, the company is headquartered in Boston, USA, with a team of 51-200 employees. The company is currently Growth Stage.