Voiceflow named in Gartner’s Innovation Guide for AI Agents as a key AI Agent vendor for customer service
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Most businesses are sitting on a goldmine they don't even realize exists. While you're pouring budget into complex marketing funnels and chasing prospects across multiple platforms, your phone number could be working as an intelligent text answering service that captures and qualifies leads 24/7. The reality is that SMS still delivers a 98% open rate—better than any email campaign you'll ever run—but most companies treat it like a one-way broadcast tool instead of the conversation starter it should be. Today, I'm sharing the exact blueprint I use to transform any phone number into an AI-powered lead qualification machine that works while you sleep, using nothing more than VoiceFlow, Make.com, and Twilio.
While everyone's chasing the latest communication channels, SMS remains the most reliable way to reach customers. 98% open rate, instant delivery, and universal compatibility across all devices. But here's the problem: most businesses treat SMS like a one-way broadcast tool.
Today, I'll show you how to build a complete AI SMS assistant using VoiceFlow and Make.com that:
This isn't theory—this is a working system, and I'm giving you the exact blueprint.
After building dozens of automation workflows, I've found this combination creates the most reliable and cost-effective SMS solution available:
Voiceflow Handles the Intelligence:
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Make.com Powers the Integration:
Twilio Provides the Infrastructure:

Step 1: Build Your Lead Qualification Agent

Create an Agent step in VoiceFlow with these exact instructions (based on the working implementation):
Step 2: Configure Agent Variables

Set up these required variables in your agent:
Type_of_business - Captures the business categoryBiggest_challenge - Stores their main customer service challengeEmail - Collects their email address for follow-upStep 3: Create Single Exit Path

Unlike complex multi-path setups, this implementation uses just one exit path:
Step 4: Add API Integration

After your agent step, add a single API block with these settings:
{{Email}}{{Biggest_challenge}}{{Type_of_business}}Step 5: Get Your VoiceFlow API Key
To connect with Make.com, you'll need your API credentials:
Step 4: Get Your Twilio Credentials
First, gather your essential Twilio credentials:
Step 5: Configure Your Messaging Service
Instead of using individual phone numbers, create a Messaging Service for better delivery rates and management:
MG...) - this is what you'll use in Make.comStep 6: Set Up Webhook URL
Configure your phone number to send SMS data to Make.com:
This webhook URL tells Twilio where to send incoming SMS data, which triggers your Make.com automation.

Here's where the magic happens. You'll need three main workflow components:
Step 6: Create the Complete SMS Processing Workflow
This is the heart of your system - a sophisticated Make.com workflow that handles SMS reception, user state management, and intelligent routing. Here's the complete breakdown:
Module 1: Webhook Receiver
Module Type: Custom Webhook
Purpose: Receives SMS data from Twilio
Output Variables: From (phone number), Body (message content), Country, etc.
Module 2: Immediate Webhook Response

Module Type: Webhook Response
Status Code: 200
Body: {"Message": "We received the request"}
Purpose: Prevents Twilio's "Accepted" status messages from appearing in SMS
Module 3: Get User State from VoiceFlow

This module queries VoiceFlow's State API to check if the user has an existing conversation:
Method: GET
URL: https://general-runtime.voiceflow.com/state/user/{{webhook.From}}
Headers:
- Authorization: {Your VoiceFlow API Key}
- versionID: production
Parse Response: Yes
According to VoiceFlow's documentation, this endpoint returns the current state of a user session, including:
variables: Custom variables you've setstack: Current conversation stack positionstorage: Persistent user dataturn: Current turn informationIf the user doesn't exist, you'll get an empty response or null data.
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Module 4: Basic Router with User Detection Logic
The router uses conditional logic to determine user type:
Route 1: New User Path

Filter Name: "New User"
Condition: {{getUserState.data.variables.user_id}} NOT EQUAL TO {{webhook.From}}
Route 2: Existing User Path

Filter Name: "Existing User"
Condition: {{getUserState.data.variables.user_id}} EQUAL TO {{webhook.From}}
New User Flow:
Module 5A: Create User Session


Module 6A: Send Initial Message


Existing User Flow:
Module 5B: Continue Conversation
Understanding VoiceFlow's Interact Response:
According to the VoiceFlow documentation, the /interact endpoint returns an array of traces representing the conversation flow execution. Key trace types include:
text: AI agent responses to send to the userspeak: Text-to-speech content (not used in SMS)choice: Multiple choice options for the userend: Conversation completion indicatorThe response structure looks like:
You'll extract the message using: {{interactResponse.data[].payload.message}}
Critical Implementation Details:
State Persistence: VoiceFlow automatically maintains conversation state using the user ID (phone number in our case). This means:
Error Handling: Add these safeguards:
Variable Access: In your VoiceFlow agent, you can access SMS-specific data:
{{request.payload}} contains the user's SMS message{{variables.business_type}}{{variables.user_id}}Step 7: Build User State Logic
The key insight: VoiceFlow maintains conversation state per user ID. Your workflow needs to:
GET /state/user/{phone_number}Step 8: Configure SMS Sending


Instead of Make.com's built-in Twilio module, use HTTP Basic Auth for better reliability:
Step 9: Set Up Your CRM Connection
Connect to Google Sheets or your preferred CRM:
Message Length Optimization SMS has a 160-character limit. Longer messages get split and cost more. Train your VoiceFlow agent with examples:
❌ "Hello! Great to meet you. I'm here to help you discover how AI could revolutionize your customer service experience..."
✅ "Hi! I help businesses improve customer service with AI. What type of business do you run?"
Error Handling Add filters in Make.com to prevent system messages from reaching customers:
Cost Management
I've deployed this exact system for a consulting firm that now sees:
The system runs completely autonomously, capturing leads while the team sleeps and qualifying prospects before they even get to the first sales call.
Want to skip the setup and deploy immediately? I've created a ready-to-use template package:
VoiceFlow Template:
Download the Voiceflow template
Make.com Workflows:
Download Make.com CRM API workflow
Download Make.com Voiceflow and Twilio connector workflow
Once your basic system is running, consider these enhancements:
Multi-Channel Expansion: Use the same VoiceFlow agent across SMS, WhatsApp, and web chat for consistent experiences.
Advanced Qualification: Add conditional logic based on business type to customize follow-up sequences.
CRM Automation: Trigger email sequences, schedule follow-up calls, or assign leads to specific team members based on qualification data.
Analytics Dashboard: Track conversion rates, response times, and conversation quality through Make.com's monitoring tools.
Building an AI SMS assistant isn't just about automation—it's about creating intelligent touchpoints that capture more leads and qualify them better than any human could at scale.
You've just learned how to build a system that combines VoiceFlow's conversational AI with Make.com's integration power and Twilio's reliable infrastructure. This creates something more valuable than the sum of its parts: a 24/7 lead generation and qualification machine that works while you focus on closing deals.
The combination of natural conversation, intelligent routing, and seamless CRM integration means every SMS interaction becomes a potential business opportunity, captured and qualified automatically.
Ready to implement this for your business? The templates above will get you started, or reach out if you need help customizing this system for your specific use case.