Black Friday / Cyber Monday Alert: Due to increased traffic demand on mobile communication networks, we are expecting potential congestion for US carrier networks during the Black Friday and Cyber Monday period. Customers may experience intermittent SMS and MMS delivery delays. Please refer to our Black Friday / Cyber Monday FAQ page and our Twilio Status page for more information.

Notice: Programmable WIreless Voice and SMS End of Life (December 2021)

On December 1, 2021, Twilio is ending support for voice calling and SMS messaging to or from Twilio Programmable Wireless SIMs using Programmable Voice and Programmable Messaging, respectively. Commands will continue to be supported to exchange machine-to-machine SMS with your applications. Users will no longer be able to configure their SIMs to use these functions after November 1, 2021 (existing configurations will continue to work through December 1). If these functions are critical for your use case, you will need to modify how your devices are using Twilio Voice and Messaging services, or migrate to an alternative provider to avoid interruptions.

This change will have the following impacts:

Voice Calling:

  • Calls from devices connected with Programmable Wireless SIMs will no longer complete. Therefore, the code residing at the voice URLs (“voice_url” and “voice_fallback_url”) on the corresponding Sim resource will not be executed. This applies to a SIM configured to make calls.
  • Calls received to Twilio Phone Numbers will no longer be forwarded to Programmable Wireless SIMs using the <Sim> TwiML noun. This applies to Phone Numbers configured to receive incoming calls.


  • You will no longer be able to send SMS to Programmable Wireless SIMs by providing the SIM SID as the “to” attribute <Message> TwiML verb. If you are receiving SMS to a Twilio Phone Number and then sending that SMS to your device connected with a Programmable Wireless SIM, the SMS will no longer be forwarded to your Programmable Wireless SIM.
  • If you are sending SMS from Programmable Wireless SIMs to any number other than 2936 (the reserved short code for exchanging commands with Programmable Wireless SIMs), the code residing at the sms URLs (“sms_url” and “sms_fallback_url”) on the corresponding Sim resource will not be executed. This applies to a SIM configured to send SMS.

Please note, you can still send and receive machine-to-machine SMS via the Commands API and reserved short code (2936).

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