Founding Engineer - Equity Based

## About the Role We are looking for a Founding Engineer to own the technical execution that takes Mosaic from a nearly complete product to a live, operating marketplace and beyond. The role is equity-based, with salary converting at our Series A. The platform is substantially built. What stands between us and launch is the completion of our e-commerce connector, end-to-end validation of the payment and order flows, and the operational readiness to support our first stores. After launch, the role expands into platform hardening, feature development, and scaling as we grow into new neighborhoods and markets. You will work directly with our CTO on architecture and design decisions. You will own day-to-day engineering execution. You set the standards, make the calls, and ship the work. ## What You Will Work On - E-commerce connector: Complete and harden our Shopify integration, covering real-time inventory sync, the full order lifecycle, webhook reliability, and the edge cases that matter in a live marketplace. A detailed technical specification covers every scenario end-to-end. The primary work between now and launch. - Marketplace payments: Validate and stress-test end-to-end payment flows built on Stripe Connect, including split payments, refunds, cancellations, and settlement. Correctness is not optional when real money is moving. - Launch operations: Work alongside the founding team to onboard our first Brooklyn stores, respond to production issues in real time, and build the operational confidence to scale. - Backend platform: Node.js, TypeScript, Express, and MongoDB Atlas. A large, well-documented REST API covering the full commerce and order lifecycle. - Mobile apps: React Native and Expo across iOS and Android, covering neighborhood discovery and checkout on the consumer side and storefront management on the retailer side. ## What We Are Looking For - Strong full-stack engineer with deep Node.js and TypeScript experience and a real production track record. You have built, shipped, and operated systems. - Payments experience in production. You understand what correctness looks like when real money is involved. Stripe experience is a strong plus; Stripe Connect experience even more so. - Comfort with third-party API integrations: webhooks, idempotency, retry logic, and the operational discipline to keep data in sync under real-world conditions. - React Native experience, or a strong React background with the appetite to own the mobile layer. - Product-minded and decisive under ambiguity. You make sound tradeoff decisions without waiting to be told what to build. - Genuine interest in the problem Mosaic is solving. These are real businesses, with real owners, operating on thin margins; we want to make a difference in their lives. ## Nice to Have - Shopify platform experience: Admin API, embedded app development, or webhook integrations. - Marketplace or multi-vendor commerce experience. - Cloud infrastructure experience: Azure, AWS, or GCP, CI/CD pipelines, and background job systems. - Geospatial or location-based feature development. ## The Commitment We expect 20 or more hours of committed, focused work per week. In return, you get a real equity stake in what we build together, direct input into engineering decisions, and a genuine say in the team and culture we grow into. ## Equity and Compensation - Equity: 5% to 10% founding equity stake, commensurate with experience and contribution. - Vesting: 6-month cliff from your start date, then monthly vesting over a 4-year total term. - Salary: You are a founding team member and equity holder. Compensation formalizes to a competitive full-time salary at our Series A.