Senior Full-Stack Engineer

**Matter** Senior Full-Stack Engineer; $200K–$250K base + equity; New York City or Miami (Hybrid)

**About Company** Matter is the first platform to pair a digital nutritionist with a physical network of restaurants that cook meals to each user's exact nutritional needs. The Matter app learns each user's goals, preferences and health data (including wearables and biomarkers) and recommends meals down to the gram. The kitchen then prepares them precisely (85g of chicken, not "small or large") for pickup or delivery.

The flagship restaurant opened in NoHo, New York in December 2025 and is already posting best-in-class sales, profitability, and repeat frequency and retention. Before launch, the team spent years building a proprietary point-of-sale and kitchen display system for gram-level customization. Matter is now launching a fully revamped consumer app built to compete head-to-head as a standalone subscription product with MyFitnessPal, MacroFactor, Lose It!, Bevel and Cronometer, while also powering restaurant ordering.

Matter is a sub-15-person team led by co-founders Jon Sherman (restaurant operations, growth, fundraising, marketing) and Kevin (founder and founding engineer of a large blockchain company, currently leading product and engineering). Kevin seed-funded the business, and Matter has since raised from angels at top-tier VC firms and from successful tech and consumer founders, with capital on the balance sheet for growth.

**About the Role** A senior full-stack engineer on Matter's small, high-velocity team, building the consumer app end to end: the AI nutrition coach, tracking and personalization features, and the in-app ordering experience that connects users to Matter's restaurants. The split between app and AI work flexes with the hire: a stronger AI engineer will lean toward the AI side (models, harnesses), a stronger full-stack generalist toward app functionality and product building. Either way they must be a strong full-stack engineer who understands how AI fits into the product. The role ships across the React Native app and the Node services behind it (PostgreSQL on AWS; LLM calls routed through OpenRouter, mostly Gemini models today), and is explicitly AI-forward: AI coding tools and agents are a core part of the daily workflow. Matter wants an engineer with real opinions on the product roadmap, not just someone who executes tickets. The engineering team is three full-time engineers plus a part-time contractor, led by co-founder Kevin as interim CTO. Matter is hiring a Chief Product Officer in parallel; this engineer partners closely with product, design and the founding team.

**Responsibilities** - Ship features end to end across the React Native consumer app and its backend services: onboarding, tracking, progress, subscriptions and in-app ordering. - Design APIs, data models and real-time features that scale with a growing subscriber base. - Own integrations with payments, notifications and health data platforms. - Build and improve LLM-powered features (AI nutrition coach, conversational and photo logging, personalized recommendations), including prompts, evals and guardrails that keep them accurate, fast and safe for health use. - Use AI coding tools and agents daily and help the team adopt practices that raise output without sacrificing quality. - Improve CI/CD, testing, monitoring and observability; own production systems, debugging, incident response and performance.

**Required Skills** A. Senior engineer with substantial professional experience, including significant full-stack work (the JD targets 10+ years; flexible for the right candidate). B. Strong full-stack engineering fundamentals; Matter's stack is TypeScript, React Native, Node, PostgreSQL and AWS, though overall engineering competence matters more than specific languages or frameworks. C. Has shipped LLM-powered features to production, with a practical grasp of prompting, evals, latency and cost. D. Uses AI coding tools and agents daily, with clear examples of how they made them and their team faster. E. Track record of shipping and maintaining high-quality consumer mobile apps. F. Solid relational database, data modeling and backend architecture experience; comfortable owning production infrastructure, deployments and monitoring. G. Personally passionate about health, wellness and fitness, with hands-on experience using macro tracking apps.

**Bonus Skills** - Subscriptions, payments or in-app commerce. - Health data integrations (Apple Health, wearables, biomarkers).

**Logistical Info** - Location: New York City or Miami (201 South Biscayne Blvd, Downtown Miami), hybrid at minimum in one of the two offices. - Compensation: $200K–$250K base + meaningful equity. - **Other:** Medical, dental and vision; flexible PTO plus paid company holidays; paid parental leave; free Matter meals.

**Ideal Background** - Ideal: a full-stack engineer at a consumer health-tech app such as WHOOP or MyFitnessPal, who personally uses macro tracking apps or wearables. Consumer health and wellness, not healthcare: strong healthcare-app profiles are a different kind of product and have been passed. - Passion for nutrition and fitness is a hard filter, confirmed by the client: they know it narrows the pool, but they want an opinionated engineer who shapes the product roadmap. - 10+ years is a guiding principle, not a magic number: 7–8 years is fine if they hit everything else. They want someone who has done this a couple of times, at a couple of companies of different stages. Framework fit matters less than overall engineering competence, so strong web engineers with less React Native are fine. - Comp note: client's base range is $200K–$250K; the rest comes from equity, which at today's valuation can take the package close to ~$500K.

**Green Flags** - Concrete, specific examples of AI tools and agents changing how they and their team ship. - Owns production end to end: deployments, monitoring, incidents. - Strong product sense and care for the end-user experience; bias toward shipping over planning. - Comfortable in ambiguity on a small, early-stage team. - Has strong, well-reasoned product opinions, as a user of nutrition/fitness apps, and pushes them into the roadmap.

**Red Flags** - No personal interest in health, fitness or nutrition, or no hands-on experience with macro tracking apps. - Only uses AI tools casually, or has never shipped an LLM feature to production. - Backend-only engineers with no consumer product experience. - Pure AI/ML specialists who aren't strong full-stack engineers. - Background in healthcare or b2b2c healthcare apps rather than consumer health tech. - Junior or mid-level engineers presented as senior.

**Interview Process** 1. Interview with co-founder Jon Sherman and Juan Angel: culture fit, whether they actually use macro tracking apps, and their personal connection to health and wellness. 2. Conversational interview plus live coding with co-founder Kevin: the candidate pulls up a non-private codebase of their own, walks through why they implemented things the way they did, and makes a live change to accomplish a specific task.