Senior Frontend Developer

Company Overview

Extuitive is a Flagship Pioneering–backed startup reimagining product innovation for the AI era. Our mission is to empower entrepreneurs and direct-to-consumer (D2C) brands with AI-driven tools that simplify, accelerate, and scale the launch of new products. Based in Cambridge, MA, we operate like a special ops unit—fast-moving, data-driven, and relentlessly focused on impact.

About the Role  

As a Senior Frontend Engineer, you’ll be instrumental in designing and building the end-to-end user experience of our platform. You’ll collaborate closely with product managers, designers, and backend engineers to translate complex requirements into elegant, responsive, and performant interfaces. Beyond building, you’ll set standards, mentor peers, and play a key role in scaling both our product and our engineering practices. 

Responsibilities

• Own the End-to-End Frontend - Translate designs (Figma, wireframes, product specs) into production-ready code. Build and maintain reusable components, design systems, and UI patterns for speed and consistency. 
• Drive Technical Quality & Best Practices - Introduce testing frameworks (unit, integration, E2E) and enforce high code quality. Establish frontend best practices (linting, CI/CD pipelines, accessibility standards). 
• Influence Architecture & Tech Choices - Make early decisions around frameworks, state management, styling systems, and frontend tooling. Advocate for the right balance of speed vs. scalability in architecture choices. 
• Wear Multiple Hats - Jump in on DevOps, analytics, or even light backend integration when needed. Help with customer-facing issues (debugging, bug fixes, UI polish) in real time. 

Requirements 

• 5+ years of professional front-end development experience. 
• Bachelor’s degree in Computer Science, Software Engineering, or equivalent practical experience. 
• Strong expertise in React, Next.js, TypeScript, HTML, and CSS (TailwindCSS or similar). 
• Solid understanding of JavaScript (ES6+), modern browser APIs, RESTful APIs, GraphQL, and WebSockets. 
• Experience with front-end performance optimization techniques such as lazy loading, code splitting, and caching. 
• Comfortable working in a fast-paced startup environment with evolving priorities and minimal oversight. 

Nice to Have 

• Experience with LangGraph, LangChain, or similar AI/agentic frameworks. 
• Exposure to AI frontend tools like AI SDK, Assistant UI, or comparable interactive agent interfaces. 
• Experience with Supabase or other modern databases. 
• Proficiency in Python for backend development or scripting. 
• Familiarity with Google Cloud Platform (GCP), AWS and Vercel for deployment and cloud workflows. 

More About Flagship Pioneering

Flagship Pioneering is a bioplatform innovation company that invents and builds platform companies, each with the potential for multiple products that transform human health or sustainability. Since its launch in 2000, Flagship has originated and fostered more than 100 scientific ventures, resulting in more than $90 billion in aggregate value. Many of the companies Flagship has founded have addressed humanity’s most urgent challenges: vaccinating billions of people against COVID-19, curing intractable diseases, improving human health, preempting illness, and feeding the world by improving the resiliency and sustainability of agriculture.  Flagship has been recognized twice on FORTUNE’s “Change the World” list, an annual ranking of companies that have made a positive social and environmental impact through activities that are part of their core business strategies, and has been twice named to Fast Company’s annual list of the World’s Most Innovative Companies. Learn more about Flagship at www.flagshippioneering.com.

Flagship Pioneering and our ecosystem companies are committed to equal employment opportunity regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender identity or Veteran status.

At Flagship, we recognize there is no perfect candidate. If you have some of the experience listed above but not all, please apply anyway. Experience comes in many forms, skills are transferable, and passion goes a long way. We are dedicated to building diverse and inclusive teams and look forward to learning more about your unique background.

Recruitment & Staffing Agencies: Flagship Pioneering and its affiliated Flagship Lab companies (collectively, “FSP”) do not accept unsolicited resumes from any source other than candidates. The submission of unsolicited resumes by recruitment or staffing agencies to FSP or its employees is strictly prohibited unless contacted directly by Flagship Pioneering’s internal Talent Acquisition team. Any resume submitted by an agency in the absence of a signed agreement will automatically become the property of FSP, and FSP will not owe any referral or other fees with respect thereto.