Firebase Multi-Tenant SaaS Developer

We're converting an existing, production-proven spa billing and management app into a subscription-based SaaS product for spas across India, with a path to native Play Store and App Store apps. The core app already works (billing, memberships, expense tracking, reporting) and is in daily use across 5 real spa outlets — the job is to rebuild it as a secure multi-tenant platform: separate, isolated data for each subscribing spa, proper authentication with staff roles, and recurring subscription billing via Razorpay. Ideal candidate has built multi-tenant SaaS products before (not just single-client apps), understands Firebase or Supabase security rules deeply, and has experience with Razorpay or similar subscription billing integrations. Experience packaging web apps into native apps via Capacitor (for Play Store/App Store submission) is a strong plus for later phases. We're starting with the backend + billing (Phase 1–2) and will extend the engagement into app store packaging once that's solid.