Building a Multi-Tenant AI Stack for 6 Businesses: How We Replaced Twilio, SendGrid, and Make.com with Supabase, VAPI, and Aster

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We deployed a vertically integrated AI infrastructure serving 6 revenue-generating businesses—real estate wholesaling, demolition, valet services, credit repair, mineral rights, and structural SaaS—all running on a single Supabase project (ID: whxtjboruayowkqyjvcq) with 98 tables, 42 Edge Functions, and 26 VAPI agents orchestrated through a custom JARVIS Brain Router. This article breaks down the technical architecture: how we eliminated dependency on Twilio and SendGrid by routing all telephony through Asterisk 18.10 on Vultr, replaced Make.com automation with Edge Functions, and built a self-hosted PBX system that handles inbound/outbound calls, IVR logic, and agent dispatch across all six business units. We'll cover Supabase schema design for multi-tenant operations, VAPI agent configuration for industry-specific workflows, and the cost/performance tradeoffs we discovered moving from SaaS platforms to infrastructure-as-code.