Phone Numbers Overview
Phone numbers are the connection point between your AI voice agents and the real world. Every inbound and outbound call flows through a phone number, and each number is linked to a specific voice provider (Retell, Vapi, or Bland).
How Phone Numbers Work
In BuildVoiceAI, phone numbers are purchased through your voice provider and managed from the dashboard. Here is the basic flow:
- Purchase a phone number through the platform (provisioned via your provider)
- Assign the number to an agent
- Inbound calls to that number are automatically routed to the assigned agent
- Outbound calls from that agent use the assigned number as the caller ID
Numbers are provider-specific. A number purchased through Retell can only be assigned to a Retell agent, a Vapi number to a Vapi agent, and so on.
Key Concepts
One Number, One Agent
Each phone number can be assigned to exactly one agent at a time. If you need an agent to handle calls from multiple numbers, you would assign each number individually (some providers support this). If you need to move a number to a different agent, you reassign it.
Provider Provisioning
Phone numbers are not purchased directly from phone carriers. Instead, BuildVoiceAI provisions numbers through the voice provider (Retell, Vapi, or Bland) associated with your account. The provider handles all telephony infrastructure, including call routing, recording, and compliance.
Client Scoping
Like agents, phone numbers are scoped to your agency. When a number is assigned to an agent, it inherits that agent’s client association. The number appears in the client portal for the relevant client if they have agent visibility enabled.
What You Can Do
Purchase Numbers
Buy new phone numbers with specific area codes directly from the dashboard. Numbers are provisioned instantly through your voice provider.
Learn more about Purchasing Numbers
Assign to Agents
Link a phone number to an agent so inbound calls are routed correctly and outbound calls show the right caller ID.
Learn more about Assigning Numbers
Manage Your Numbers
View, nickname, and organize your phone numbers. Release numbers you no longer need.
Learn more about Managing Numbers
Phone Numbers and Billing
Phone number costs are determined by your voice provider, not by BuildVoiceAI. Monthly fees and per-minute rates vary by provider and region. Check your provider’s pricing page for current rates.
The BuildVoiceAI platform rate of $0.15/min applies to call duration, separate from any number rental fees your provider charges.
Start with one or two numbers to test your setup before purchasing numbers in bulk. You can always add more as you onboard clients.
Next Steps
- Purchasing Numbers — Buy phone numbers through the platform
- Assigning to Agents — Connect numbers to your AI agents
- Managing Numbers — Organize and maintain your number inventory