### Answer Retell AI uses a pay-as-you-go model at $0.07+ per minute for AI Voice Agents with no platform fees - this applies to both inbound and outbound calls. [(1) ]() [(2) ]() Per-minute rates: The base cost is consistent regardless of direction. The sources show the same $0.07/minute rate used in both inbound and outbound cost calculations. Telephony/carrier fees: Retell AI's integrated approach means the single per-minute fee covers voice synthesis, speech recognition, LLM processing, and basic telephony. The platform supports Twilio, Vonage, SIP, or verified numbers out-of-the-box. [(1) ]() Additional costs to account for: - **Voice model choice**: ElevenLabs voices cost $0.07/min, while OpenAI/Deepgram voices cost $0.08/min [(2) ]() - Token-based LLM pricing (effective June 1st) : Prompts up to 3,500 tokens follow the flat rate; prompts exceeding 3,500 tokens scale proportionally in cost [(3) ]() - **Short calls with Dynamic AI First Sentence**: Calls using this feature have a minimum billable duration of 10 seconds - **Optional add-ons**: PII redaction is $0.01/min, and HIPAA/PCI compliance options are available at enterprise pricing [(3) ]() [(2) ]() For your lead qualification use case, the sources model outbound campaigns at the same $0.07-$0.08/minute base rate as inbound. [(1) ]() [(2) ](

tellai.com/resources/inbound-vs-outbound-callers-pricing-comparison-2025)

​ To learn more, see the sources I considered: [[1] ](https://www.retellai.com/resources/outbound-ai-caller-cost-breakdown) [[2] ](https://www.retellai.com/resources/inbound-vs-outbound-callers-pricing-comparison-2025) [[3] Platform Changelogs | Retell AI](https://www.retellai.com/changelog) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, Retell AI supports leaving voicemails when your agent detects one during outbound calls. [(1) ]() ## Voicemail Detection & Handling You can configure your agent to either hang up or leave a message when it detects a voicemail. The options are: - **Hang up**: The agent disconnects when voicemail is detected - **Leave a message**: The agent leaves a message after it's the agent's turn to speak. You can use either: - **Static message**: A pre-recorded message like

Hi, this is {{your name}}, please give us a callback tomorrow at 10am.

- **Prompt**: A dynamically generated message based on instructions you provide, like

summarize the call and ask user to call back

Dynamic variables are supported for both static messages and prompts. Voicemail detection runs for the first 3 minutes of the call by default. ## Callback to the Same Number Regarding your question about leads calling back the same outbound number—the sources indicate that phone numbers can be configured with both an

outbound_agent_id

and an

inbound_agent_id

. [(2) ]() This means you can set up a single phone number to handle both outbound calls and receive inbound callbacks. To configure this, you would update your phone number to have both agents assigned:

javascript
const phoneNumberResponse = await client.phoneNumber.update('+14157774444', {
  inbound_agent_id: 'oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD',
  outbound_agent_id: 'oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD',
}) ;

So you don't necessarily need to ask leads to call a different number—you can configure the same number to route inbound calls to your voice agent.

​ To learn more, see the sources I considered: [[1] Handle voicemail](https://docs.retellai.com/build/handle-voicemail) [[2] 404 Error on Create a Phone Call](https://retell.discourse.group/t/404-error-on-create-a-phone-call/22) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, you can schedule follow-up outbound calls if a lead doesn't pick up. The sources mention that Retell AI supports batch calling capabilities for outbound campaigns, which lets businesses automate thousands of outreach calls including sales follow-ups and appointment reminders. [(1) ]() When voicemail is detected, the call will have a disconnection reason of

voicemail_reached

if the defined action was taken successfully. [(2) ]() You can use this information via webhooks to trigger retry logic in your system. The recommended approach would be: 1. Use the

call.ended

webhook to detect when a call ends with

voicemail_reached

or wasn't answered 2. Schedule a retry call through your backend logic (e.g., a few hours later) 3. Use the Create Phone Call API to initiate the follow-up outbound call The sources don't document a built-in automatic retry/scheduling feature within Retell itself, so you would need to implement the scheduling logic on your end (using a job scheduler, cron, or similar) that triggers the outbound call API at the desired time. For batch operations, Retell's batch calling feature can help you manage large volumes of outreach calls with scheduling capabilities. [(1) ]()

​ To learn more, see the sources I considered: [[1] 2025 B2B Guide to AI Phone Calls & Voice Agents | Retell AI | Retell AI](https://www.retellai.com/blog/b2b-guide-to-ai-phone-calls) [[2] Handle voicemail](https://docs.retellai.com/build/handle-voicemail) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Based on the available sources, I don't have documentation on a standalone "greeting-only" mode for inbound calls that would avoid using an inbound agent. The sources show that phone numbers can be configured with an

inbound_agent_id

to handle incoming calls. [(1) ]() If

inbound_agent_id

is set to

null

, the number "would not accept inbound call." This suggests two options for your scenario: 1. Assign an inbound agent - Configure a simple agent with minimal logic that just delivers your greeting message and ends the call 2. Leave inbound unconfigured - The number won't accept inbound calls (callers would get no answer/busy signal) For a simple greeting without full conversational AI, you might consider handling this at the telephony layer (e.g., Twilio's built-in IVR/voicemail features) before it reaches Retell, since Retell's value is in conversational AI agents rather than static message playback. Would you like a general answer on how this might be approached, or should I point you to support for confirmation on whether a minimal-cost greeting option exists? Check out these potentially useful sources: - [Import Phone Number]() - [How to Choose the Right Telephony System in 2024 | Retell AI]()

​ To learn more, see the sources I considered: [[1] Import Phone Number](https://docs.retellai.com/api-references/import-phone-number) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.