Full-Stack Engineer - Marketplace MVP in 4 weeks (React/Node/Postgres)

We're looking for a senior full-stack developer to turn our fully built React prototypes into a production platform. This is not a greenfield design project — every screen, component, user flow, data model, and business rule is already defined in working interactive prototypes. You're wiring it to a real backend. You'll be working alongside one other developer and directly with the founder and operational lead (who runs day-to-day surrogacy operations). AI coding tools (Cursor, Claude Code) are expected and we're looking to move fast. What's already built: Two complete React portals (surrogate-facing and agency-facing) covering auth flows, batch-based candidate distribution, agency acceptance workflows, surrogate selection with IP preference, compensation transparency tools, compatibility scoring, document vault, milestone tracking, payment tracking, review system, and admin escalation flows. All business logic is documented and mapped to our legal agreements. What you're building: Auth and role-based access (surrogate, agency, admin). PostgreSQL schema mirroring the existing data models. API layer (Node or Python). Stripe Connect integration via ACH/card, auto-charge on surrogate selection, pre-auth at acceptance, failed payment handling, referral credit system. Secure document storage (S3). Real-time notifications. Escrow provider consent flows. BornVia admin dashboard. Deployment and CI/CD. You're ideal if you: Have shipped a marketplace or two-sided platform before. Have integrated Stripe Connect (not just Stripe Checkout, Connect specifically). Can read a React prototype and extract the spec without a PM translating. Are comfortable owning backend architecture decisions. Use AI tools daily and ship fast. Timeline: Working MVP in 3-4 weeks. The product thinking is done so this is just execution.