How I Built a Multi-Tenant WhatsApp Automation Platform Using n8n and WAHA

TL;DR: I run WhatsApp automation workflows for 50+ businesses on shared infrastructure using n8n (queue mode), WAHA (unofficial WhatsApp Web API), Supabase, and Chatwoot. This is the technical deep-dive into how the multi-tenant architecture works, the problems I solved, and what it costs. The Problem I'm a solo automation engineer based in Israel. My clients are mostly small-to-medium businesses that need WhatsApp automation — appointment reminders, lead qualification, order confirmations, customer support bots. Each client has different workflows, different WhatsApp numbers, and different business logic. The naive approach is spinning up a separate n8n instance per client. That works for 3 clients. At 50+, you're managing 50 Docker stacks, 50 PostgreSQL databases, 50 sets of credentials. Updates become a nightmare. Monitoring becomes impossible. I needed a single n8n instance that could: Handle webhooks from 50+ WhatsApp sessions simultaneously Route messages to the correct workflow