I need a senior full-stack developer who can take a lean SaaS MVP from spec to production over the next three-to-four months. The product is a multi-tenant web app that gives small-business owners a personalised AI “Business Copilot.” Core objective The single most critical feature is the daily, AI-generated business briefing. It will analyse each account’s financial data—focusing first on expense tracking—and surface clear, actionable insights every morning. Key scope • Multi-tenant user management with secure email/password and Google OAuth sign-in • Gmail connection via OAuth 2.0 so future modules can suggest email replies (not in first release, but the hook must be there) • Financial data ingestion (initially CSV upload or lightweight API) used by the LLM to create briefings that spotlight spending patterns and cost-saving opportunities • Stripe integration for self-serve subscription and plan management • Clean, test-covered architecture that can scale beyond the MVP phase • Cloud deployment with CI/CD, environment-based secrets, and role-based access controls Tech preference I’m open to the stack you’re most productive with—common choices like Node/TypeScript, Python/FastAPI, or Ruby on Rails are fine so long as they pair well with PostgreSQL, Redis, and an LLM provider such as OpenAI. Deliverables 1. End-to-end SaaS application in a production cloud account 2. Source code in Git with meaningful commits, tests, and README setup guide 3. Technical hand-over session and short architecture document Acceptance criteria • A new tenant can sign up, connect Gmail, upload a simple financial file, and receive an AI briefing that references their latest expenses. • Stripe checkout completes successfully and locks premium features if a payment lapses. • All data for one tenant is completely isolated from others. If you’ve shipped SaaS products with similar integrations—especially LLM-powered dashboards—let’s talk.