U.S.-Based React/Firebase SaaS Technical Lead / Architecture Reviewer

We are looking for a U.S.-based senior React/Firebase technical lead or software architect to help review and guide an existing SaaS product to pilot launch. The product is already built and deployed in staging. This is not a greenfield build. We need an experienced technical partner who can inspect the current architecture, review contractor work, identify launch risks, and help sequence the remaining work before pilot. Current stack: * React / TypeScript * Firebase Auth * Firestore * Firebase Storage * Firebase Cloud Functions * Firebase Hosting / GCP * GitHub The app is a multi-tenant SaaS platform with organizations, locations, employees, role-based permissions, training modules, SOPs, communications, request-off workflows, handbook acknowledgements, and admin consoles. We need help with: * Reviewing the existing React/Firebase architecture * Reviewing Firestore rules, Storage rules, Cloud Functions, auth/custom claims, and tenant isolation * Reviewing PRs and contractor work * Advising on remaining pilot-readiness work * Helping sequence frontend cleanup, UX/UI polish, admin console structure, and final security review * Identifying risks before real pilot customers are onboarded Important experience: * React + TypeScript SaaS applications * Firebase Auth / Firestore / Cloud Functions * Multi-tenant architecture * Role-based access control * Security-minded code review * GitHub branch / PR workflow * Ability to explain technical tradeoffs clearly We would like to start with a small paid technical review first. If it is a good fit, this may turn into an ongoing technical lead/advisor role. We are not looking for someone to blindly rebuild the app. We need senior judgment, architecture review, launch-risk identification, and practical guidance.