Multi-Tenant WhatsApp Automation SaaS

Project Title: Build a Multi-Tenant B2B SaaS Automation Hub (WhatsApp CRM, n8n, & AI Integration)

Project Description:
We are looking for an expert backend and automation developer to build a scalable, multi-tenant B2B SaaS automation platform tailored for e-commerce stores and real estate agencies in Pakistan.

Core Architecture & Requirements:
1. Multi-Tenant Infrastructure: Capable of managing multiple business clients (e-commerce vendors & real estate agents) under a single self-hosted backend.
2. WhatsApp Cloud API Integration: Seamless webhook handling for incoming customer chats, automated replies, and instant lead routing.
3. n8n Workflow & AI Engine: Integrating self-hosted n8n instances, PostgreSQL database, and AI (OpenAI/Claude) to understand and reply in Roman Urdu/Urdu and English.
4. Smart Billing & Wallet System:
- Prepaid automated wallet system (minimum balance floor with auto-recharge reminders).
- Dynamic commission/fee calculation logic based on transaction value tiers (e.g., lower-tier e-commerce products vs. high-ticket real estate properties with custom slab deductions).
5. Data Sync: Automated synchronization with Google Sheets, custom CRMs, and Shopify order status updates.

Deliverables:
- Fully functional, secure multi-tenant backend (n8n + DB).
- Automated webhook triggers and reliable error-handling protocols.
- Clean documentation and a 5-day testing/stabilization phase before final milestone release.

Please share your past experience with n8n, WhatsApp Business API, and multi-tenant SaaS architecture when applying. Budget is flexible based on expertise and quality.