Overview
When an autoresponder is configured for Twilio phone numbers, incoming calls trigger a pre-recorded audio message. The audio file may be hosted externally or within Twilio Assets. This article explains how Twilio bills for:
- Incoming calls
- Playing audio messages
- Use of TwiML Bins, Functions, or Assets
- Approximate cost per call
Environment
Twilio Console
What You Need To Know
1. Incoming Call Charges
Twilio bills for inbound calls to Twilio numbers at standard pay-as-you-go voice rates. For example, US local numbers are typically billed at $0.0085 per minute. Rates may vary by country and number type. Refer to the Programmable Voice Pricing page for current rates.
2. Playing Audio Messages
There is no additional charge for using the <Play> verb in TwiML to play audio messages during a call. The only cost incurred is the duration of the call itself.
3. TwiML Bins, Functions, and Assets Pricing
- TwiML Bins: Free to create and execute. No charge for hosting or serving TwiML.
- Functions: Billed per invocation. The first 10,000 invocations per month are free; after that, $0.0001 per invocation.
- Assets: Billed per request. The first 10,000 requests per month are free; after that, $0.0001 per request. Charges apply only if the audio file is hosted in Twilio Assets and the free tier is exceeded.
For more details, see the Twilio Serverless Pricing page.
4. Hosting Location of Audio File
- External Hosting: No Twilio charge for fetching audio from an external URL.
- Twilio Assets: Charges apply only after the free tier is exceeded.
5. Approximate Cost Per Call
- If the call lasts one minute and the audio is hosted externally:
- Inbound call: $0.0085
- Audio fetch: $0.00
- Total: $0.0085 per minute
- If the audio is hosted in Twilio Assets and the free tier is exceeded:
- Add $0.0001 per request
Conclusion
- Twilio charges for the duration of inbound calls. TwiML Bins are free.
- Functions and Assets are billed per invocation/request after the free tier.
- Playing audio messages does not incur extra charges beyond the call duration. Hosting the audio externally avoids Asset charges.