Subscription based mobile app help

I'm building a subscription-based app using Ionic React on the frontend and Slim 4 (PHP) with MySQL on the backend. I need a developer to help implement secure authentication, subscription validation, and enterprise access, with support for offline use.
✅ What I Need:
🔹 Authentication
Secure login/logout system
Sign-up and password management
JWT-based session management (or similar)
Store auth/session securely on the device for offline use
🔹 Subscription Validation
Validate subscriptions (individual and enterprise)
Persist access data locally so users can access features offline
Sync subscription status with backend when online
🔹 Enterprise Accounts
Companies can create a master account
Company accounts can invite/add multiple users
Option to invite users via email or access code
🔹 Backend Integration
Slim 4 backend using MySQL
You’ll help build or connect endpoints for login, token generation, subscription checks, etc.
💻 Tech Stack
Frontend: Ionic React
Backend: Slim 4 (PHP)
Database: MySQL (via MAMP during development)
📝 Deliverables
Fully working authentication system
Local storage of access/session data for offline use
Subscription checks with both individual and enterprise support
Backend endpoints (if needed)
Basic security best practices
🎯 Ideal Developer
Experience with authentication flows (especially offline-capable apps)
Comfortable with Slim 4 / PHP / MySQL
Can suggest and implement secure offline-first strategies
Clear communicator who can collaborate and explain architecture choices

I would also consider using a service like RevenueCat or a similar solution and have someone set it up for my app. 
 ... Show more