Full-Stack Developer Needed: Multi-Tenant SaaS Build (React / Node / Meta Ads API)

Project: Build a multi-tenant SaaS web application from a detailed existing spec. This is a self-service advertising platform: business owners connect their own Meta (Facebook/Instagram) ad account and the app helps them generate ad creative, launch campaigns, and manage performance. Software Stack: • Frontend: React + TypeScript (Vite), Tailwind, shadcn/ui • Backend: Node + TypeScript, Postgres, a background worker/queue tier • Integrations: Meta Marketing API, Stripe, an AI text-generation API, a video render API, CRM APIs • Hosting: Vercel (frontend) + Railway (backend) + Neon (Postgres) + Cloudflare R2 (storage) Scope (high level): • User accounts and multi-tenant data isolation • Meta ad-account connection (OAuth), campaign launch, lead and metrics sync • AI-assisted ad copy generation and static image creative • A rules-based optimization engine for ad performance • Video creative via a third-party render API • Subscription billing and an admin panel Important: a detailed, phase-by-phase technical brief already exists (roughly 10 phases, fully specified). Shortlisted candidates will receive the full brief under an NDA and will be asked to estimate hours per phase, so you are not quoting blind. What I am looking for: • Strong full-stack experience with React + TypeScript and Node + TypeScript • Real, demonstrable experience integrating the Meta Marketing API (this is the part that separates serious candidates; please mention specific projects) • Comfort with third-party API integration generally (payments, webhooks, OAuth) • Clear communication and the ability to break work into reviewable chunks