The tech stack (what actually runs it)

Retell AI for voice, Twilio for WhatsApp, Resend for email, Python for parsing, Google Calendar API for booking.

2 min read

#The actual tech stack

#Core services

Service	Purpose	Cost/month	Notes
Retell AI	Voice agent (calls + IVR)	$20–200	Best voice quality, handles Arabic/English switching
Twilio	WhatsApp Business API	$50–500	Required for WhatsApp in UAE
Resend	Email sending (lead notifications)	$0–20	For agent notification emails
Python/Flask	Email parser + orchestration	$0	Runs on a cheap VPS ($5–10 DigitalOcean)
Google Calendar API	Booking sync	$0	Free, standard OAuth
PostgreSQL	Lead + conversation storage	$5–10	Or even SQLite for MVP

#Architecture diagram (text)

Portal Email → Resend → Python Parser → [Qualification Engine]
                                         ├─ Hot → Retell Call + Twilio WhatsApp
                                         ├─ Warm → Twilio WhatsApp only
                                         └─ Cold → Archive
                                         ↓
                              Calendar booking (Google API)
                                         ↓
                              CRM webhook (Zoho/HubSpot/Sheets)

#Why these tools and not others

Retell AI (not ElevenLabs): Retell has built-in phone calling, not just TTS. The call actually connects to the lead's phone.
Twilio WhatsApp (not MessageBird): Twilio has better UAE WhatsApp Business API support and documentation.
Resend (not SendGrid): Resend has better deliverability for .ae domains and cheaper pricing.
Python (not Node.js): You're orchestrating I/O-heavy workflows. Python's async + regex parsing of messy portal emails is battle-tested.

#Cost breakdown per client (Growth tier)

Component	Monthly cost	Your margin
Retell AI	$50	AED 300 revenue, AED 180 cost
Twilio	$80	AED 300 revenue, AED 240 cost
Server (DO VPS)	$10	Shared across clients
Resend	$5	Shared across clients
Total cost	$140	~AED 2,300 margin per client

#Key insight: the server never sends a lead

The server receives portal emails, parses them, and sends WhatsApp/calls. It never sends email to leads (avoids spam filters). All lead contact is via WhatsApp (read receipts) or voice calls (answering machine fallback).

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Step 1 — Email parser

Resend inbound webhook that parses Bayut/PF emails into structured lead data.

2 min