Voice Broadcast API

Voice API
Quick Start Guides

The Voice Broadcast API is a hosted, programmable web service that can send or receive up to 12,000 Tier 1 quality phone calls per minute using text-to-speech, pre-recorded sound files, or both. Esendex’s API delivers clear voice calls over its own network of geographically dispersed server farms.

Create a client in any programming language to interact with the API. Look at our Quick Start Guides to get started with some of the most common platforms. If you have questions, check out our FAQ or contact us.

Call Scripts

When you make a call with the API, you can specify a call script in the TextToSay parameter. Various commands are available to control the content, flow, and text-to-speech options of your script.

Technical Information

Preferred Phone Number Formats

For USA/Canada numbers use this format:

  • 1 + NPA + NXX + XXXX
  • 1 + (Area Code) + Number
  • Example: (1 + 757 + 544 + 9510) = 17575449510

For international numbers use this format:

  • 0 + 11 + Country Code + Phone number

Voice Broadcast API coverage is worldwide. Calls outside of the U.S and Canada incur extra charges based on carrier.

IP Ranges

To use the API, make sure to allow communication with the following IP address ranges:

  • –
  • –

Reverse Notify / Replay Line

If you use 1-866-665-4386 as your Caller ID, the system will allow “reverse notifications.” This will enable users who missed a call to ring back this number and get the last message they missed. Keep in mind that this counts as one transaction.

Benefits include:

  • Enable your clients to listen to something they might have missed in the original notification.
  • Get your message out to people who just call back and never check voicemail (great for collection efforts).
  • Increase promotion ability and revenue for resellers of the API.

Incoming Calls / Phone Numbers

Esendex’s API supports incoming call scripts. Please send us a request or call (757) 544-9510 to get incoming phone numbers that run Esendex call scripts. We provide toll-free and local numbers by request. It takes approximately 5–7 business days to get a number.

Let’s start sending, together.