Full-Stack Developer

Position Type: Full-Time | Remote Working Hours: Minimum 4 hours of overlap with U.S. Eastern Time Employment Type: Long-Term Contract About the Role We’re looking for a senior Full-Stack Developer to build and evolve Sergio , an AI assistant designed for home service businesses, starting with cleaning companies. You’ll own features across the frontend, backend, data, billing, integrations, and AI capabilities while working closely with AI coding tools such as Claude Code and Cursor. This role is ideal for someone who can move quickly, make sound technical decisions independently, and consistently ship polished, production-ready work. Key Responsibilities Product Development Build and iterate on Sergio using Next.js App Router, TypeScript, and Tailwind CSS. Develop responsive, production-ready features and screens deployed through Vercel. Turn product requirements and rough mockups into polished user experiences. Backend & Data Architecture Design and maintain multi-tenant data structures using Supabase and PostgreSQL. Implement and maintain Row-Level Security (RLS) to properly isolate customer data. Manage authentication flows and backend data architecture. Billing & Integrations Own the Stripe billing integration, including subscriptions, webhooks, plan management, and edge cases. Build and maintain reliable SMS and email delivery pipelines. Develop and maintain third-party integrations as the product evolves. AI & LLM Development Build AI-powered product features using the Anthropic API or comparable LLM APIs. Work hands-on with prompt design, response handling, and LLM integration. Ensure AI-generated outputs are useful, reliable, and naturally integrated into the product experience. UI/UX & Frontend Quality Build polished, responsive interfaces from rough mockups without requiring constant designer involvement. Apply strong UX/UI judgment across components and user flows. Maintain a high standard of usability and visual quality. AI-Assisted Development Work daily with AI coding agents such as Claude Code and Cursor. Review AI-generated code critically and identify errors, security issues, and architectural problems. Guide AI tools toward production-quality implementations rather than relying on them blindly. Testing & Delivery Write Playwright or comparable end-to-end tests for critical product flows. Ship small, focused changes to the development branch consistently. Communicate progress, decisions, blockers, and technical reasoning clearly through async written updates. Required Experience & Skills Senior-level experience building and shipping full-stack web applications in production. Strong hands-on expertise with Next.js App Router and TypeScript . Experience with Supabase or another PostgreSQL-backed platform . Strong understanding of multi-tenant data modeling and Row-Level Security . Experience integrating Stripe subscription billing , including webhooks and edge cases. Hands-on experience…