Voice AI¶
Deploy AI agents that make and receive phone calls. 4Geeks Voice AI uses VAPI for telephony, ElevenLabs for voice synthesis, and Deepgram for speech-to-text — creating natural-sounding AI phone agents.
Overview¶
Voice AI capabilities:
- Inbound Calls — AI answers incoming calls 24/7
- Outbound Calls — AI makes calls for campaigns, follow-ups, reminders
- Phone Provisioning — Get dedicated phone numbers for your agents
- Calling Campaigns — Bulk outbound call campaigns with CSV upload
- Call Analytics — Monitor call duration, outcomes, and transcripts
Setting Up Voice AI¶
Step 1: Choose Voice Channel¶
When creating an agent:
- Open the Agent Studio
- At the Channel step, select Phone
- The voice AI configuration options appear
Step 2: Provision a Phone Number¶
- Click Connect Phone Number
- Choose a number:
- Search for a new number — By country code and area code
- Use an existing number — From your account
- Confirm the number assignment
- The number is linked to your agent
Step 3: Configure Voice Settings¶
| Setting | Description | Options |
|---|---|---|
| Voice Provider | Text-to-speech engine | ElevenLabs, PlayHT |
| Voice | Specific voice selection | Multiple voices per provider |
| Transcription | Speech-to-text engine | Deepgram (default) |
| Language | Call language | English, Spanish, Portuguese, French |
| First Message | Opening greeting | Custom message |
| End Call Phrase | How the agent ends calls | Configurable |
Step 4: Configure AI Model¶
| Setting | Description | Default |
|---|---|---|
| LLM Provider | Language model | OpenAI |
| Model | Specific model | gpt-4o-mini |
| System Prompt | Agent behavior instructions | Auto-generated or custom |
| Temperature | Response creativity | 0.7 |
VAPI Integration¶
4Geeks Voice AI is powered by VAPI (Voice API):
What VAPI Provides¶
| Feature | Description |
|---|---|
| Telephony | Phone number provisioning and call routing |
| Assistant Management | Create and configure AI assistants |
| Tool Execution | Server-side tool calls during conversations |
| Call Recording | Record and store call audio |
| Transcripts | Real-time and post-call transcripts |
VAPI Assistant Configuration¶
When you deploy a voice agent, 4Geeks automatically creates a VAPI assistant with:
- Your system prompt
- Selected voice and transcription settings
- Tool configurations (calendar, CRM, etc.)
- Phone number assignment
Server-Side Tools¶
Voice agents can execute tools during calls:
| Tool | Description |
|---|---|
| Calendar Booking | Schedule appointments during the call |
| CRM Lookup | Look up customer information |
| CRM Update | Update records after the call |
| Transfer Call | Transfer to a human agent |
| End Call | Politely end the conversation |
Tools are executed via the vapi-tool-handler edge function.
Outbound Calling Campaigns¶
Create and manage bulk outbound call campaigns.
Creating a Campaign¶
- Navigate to the Campaigns tab in AI Agents
- Click Create Campaign
- Configure:
- Campaign Name — Descriptive name
- Agent — Which voice agent to use
- Phone List — Upload a CSV of phone numbers
- Schedule — When to make calls (immediate or scheduled)
- Concurrency — How many calls simultaneously
- Click Launch Campaign
CSV Format for Phone Lists¶
phone_number,customer_name,notes
+15551234567,John Doe,Follow up on quote
+15559876543,Jane Smith,Appointment reminder
+15555555555,Bob Wilson,Payment reminder
Campaign Dashboard¶
Monitor campaign performance:
| Metric | Description |
|---|---|
| Total Calls | Number of calls in the campaign |
| Completed | Calls that reached a person |
| No Answer | Calls that went to voicemail or weren’t answered |
| Failed | Calls that failed (invalid number, etc.) |
| Average Duration | Mean call length |
| Success Rate | Percentage of completed calls |
Campaign Status¶
| Status | Description |
|---|---|
| Pending | Campaign created, not yet started |
| Running | Calls are being made |
| Paused | Campaign temporarily stopped |
| Completed | All calls have been attempted |
| Failed | Campaign encountered an error |
Campaign Controls¶
- Pause — Stop making new calls (in-progress calls continue)
- Resume — Continue from where the campaign paused
- Cancel — Stop the campaign entirely
- View Logs — See individual call results
Call Logs¶
Each call in a campaign is logged:
| Field | Description |
|---|---|
| Phone Number | Number called |
| Status | Completed, No Answer, Failed |
| Duration | Call length in seconds |
| Transcript | Full conversation transcript |
| Recording | Call recording (if enabled) |
| Outcome | Result summary |
| Timestamp | When the call was made |
Phone Number Management¶
Viewing Connected Numbers¶
- Navigate to the Channels tab
- View all connected phone numbers:
| Number | Agent | Status | Country |
|---|---|---|---|
| +1 (555) 123-4567 | Sales Agent | Active | US |
| +506 2222-3333 | Receptionist | Active | CR |
Disconnecting a Number¶
- Navigate to Channels
- Find the phone number
- Click Disconnect
- Confirm
The number is released and can be reassigned later.
Call Quality¶
Voice Synthesis¶
ElevenLabs provides natural-sounding voices:
- Multiple voice options per language
- Adjustable speed and pitch
- Emotional tone control
- Low latency streaming
Speech Recognition¶
Deepgram provides accurate transcription:
- Real-time transcription during calls
- Support for accents and dialects
- Punctuation and formatting
- Multi-language support
Latency Optimization¶
The voice AI stack is optimized for low latency:
| Component | Typical Latency |
|---|---|
| Speech-to-Text | 300ms |
| LLM Processing | 500ms |
| Text-to-Speech | 400ms |
| Total | ~1.2 seconds |
Billing¶
Voice AI calls consume tokens from your agent balance:
| Component | Cost |
|---|---|
| Per-minute charge | Varies by destination country |
| LLM tokens | Standard token pricing |
| Voice synthesis | Included in per-minute charge |
| Transcription | Included in per-minute charge |
Auto-refill ensures your agents never stop mid-call.
Best Practices¶
- Write clear prompts — Voice agents need concise, conversational prompts
- Set expectations — The first message should clearly state it’s an AI
- Test thoroughly — Use the playground before deploying to production
- Monitor transcripts — Review call logs to improve agent performance
- Start small — Begin with a small campaign, then scale up
What’s Next¶
- Knowledge Base — Add domain knowledge to voice agents
- Website Analysis — Auto-generate voice agent prompts
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