### Answer Retell AI uses per-minute pricing for voice agents at $0.07-$0.08 per minute depending on the voice provider (ElevenLabs voices cost $0.07/min, OpenAI/Deepgram voices cost $0.08/min) . [(1) ]() Regarding your specific questions: Minimum call duration/credits: The available sources don't specify a minimum credit charge or baseline per call. The pricing model described is purely per-minute usage-based with no platform fees. Twilio integration: Using Twilio as your telephony provider won't change Retell AI's per-minute pricing structure—Retell charges for the Conversation Voice Engine separately from telephony costs. However, one relevant note from a community discussion: if you're using Twilio's AMD (MachineDetection/AsyncAmd) , this can cause extra charges even if the user doesn't pick up. Disabling Twilio AMD and letting Retell's voicemail detection handle it instead may help. [(2) ]() Voicemail detection settings you can configure: - `voicemail_detection_timeout_ms`: Configures when to stop running voicemail detection (minimum 5,000ms, maximum 180,000ms, default 30,000ms) [(3) ]() - `voicemail_option`: Set actions for when voicemail is detected (hangup or leave a message) I don't have specific documentation on minimum credit charges or why you're seeing a 7-credit baseline. I'd recommend reaching out to Retell AI support directly for clarification on your billing specifics: - [Contact Sales]() - [GitHub]() Would you like a general answer about typical voice AI billing practices instead?

​ To learn more, see the sources I considered: [[1] ](https://www.retellai.com/resources/inbound-vs-outbound-callers-pricing-comparison-2025) [[2] URGENT: AMD (Answering Machine Detection) for outbound call, Voice Mail setting does not work](https://discord.com/channels/1186424376300679209/1397140044359274587) [[3] Update Voice Agent](https://docs.retellai.com/api-references/update-agent) ​

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