Senior Fullstack Developer (Next.js, Supabase) - Agentic AI Platform

A company is building an agentic AI platform with 7 core systems serving DTC e-commerce brands. They have a completed, production-quality frontend (10 pages) and need a senior engineer to build the entire backend, AI systems, and integrations.

Core Systems to Build: 1) AI-powered discovery engine with autonomous agents that find, score, and select prospects. 2) Email infrastructure with multi-account sending, domain warmup, deliverability monitoring. 3) AI outreach sequences with personalized LLM-generated messaging. 4) AI reply processing with classification, routing, context-aware responses. 5) E-commerce shipping integration. 6) Analytics and reporting API. 7) Learning database that improves from interactions.

20 weeks contract, 40 hours/week.

Must-Have: Expert in Next.js 14+ (App Router) with TypeScript. Expert in Supabase/PostgreSQL with multi-tenant B2B architecture. Strong Claude/OpenAI API experience with agentic AI patterns. Proven email infrastructure experience (warmup, deliverability, SMTP at scale). Background job pipeline implementation. Shipped at least 1 AI-integrated SaaS product to production. Stripe subscription billing experience.

Nice-to-Have: Shopify API/app development. Web scraping (Apify, Playwright). Meta/TikTok APIs.

Tech Stack: Next.js 16, React 19, TypeScript, Tailwind CSS, Supabase, Claude API (Anthropic), Vercel, Inngest or Trigger.dev, Shopify API, Resend/SendGrid, Apify, Stripe.