---
title: How can I use SMSGatewayCenter’s Voice Call API to automate Bulk Voice and OBD campaigns, and what are the key parameters?
description: "SMSGatewayCenter offers a robust [Voice Call API](https://www.smsgatewaycenter.com/developer-api/voice-call-api/) to automate Bulk Voice and Outbound Dialing (OBD) campaigns, making it easy to integrate voice messaging into your systems. Here’s how it works and the key parameters: - **How the Voice Call API…"
url: "https://www.smsgatewaycenter.com/blog/kb/voice-call-api-bulk-obd-automation-smsgatewaycenter/"
updated: "2025-05-16"
category: OBD Voice Call
---

# How can I use SMSGatewayCenter’s Voice Call API to automate Bulk Voice and OBD campaigns, and what are the key parameters?

SMSGatewayCenter offers a robust [Voice Call API](https://www.smsgatewaycenter.com/developer-api/voice-call-api/) to automate Bulk Voice and Outbound Dialing (OBD) campaigns, making it easy to integrate voice messaging into your systems. Here’s how it works and the key parameters:

- **How the Voice Call API Works**:
  - The API allows you to send voice messages programmatically, fetch reports, and automate campaigns via your CRM, ERP, or custom app.
  - Supports multiple methods: sending pre-recorded audio, using Text-to-Speech (TTS), or selecting audio from a library.
- **Steps to Use the API**:
  - **Sign Up**: Create an account on SMSGatewayCenter.
  - **Access API Documentation**: Find the Voice Call API details in your dashboard or at [https://www.smsgatewaycenter.com/developer-api/voice-call-api/](https://www.smsgatewaycenter.com/developer-api/voice-call-api/).
  - **Set Up the API Call**: Use the endpoint https://unify.smsgateway.center/VoiceApi/send with the required parameters.
- **Key Parameters**:
  - userId and password: Your SMSGatewayCenter credentials.
  - sendMethod: Set to simpleVoice for basic voice calls.
  - audioType: Choose the audio source:
    - audio: Upload a pre-recorded file (e.g., /path/to/file).
    - t2s: Use Text-to-Speech (e.g., msg=Your OTP is 1234).
    - library: Select from a pre-existing audio library (e.g., libraryId=863713123).
  - mobile: List of recipient numbers (e.g., 99999999xx,9999999xxx).
  - reDial: Number of redial attempts for unanswered calls (e.g., 2).
  - redialInterval: Time between redials in minutes (e.g., 5).
  - format: Response format (e.g., json).
- **Example API Call**:
  - To send a TTS voice message:
    https://unify.smsgateway.center/VoiceApi/send?userId=YourUsername&password=YourPassword&sendMethod=simpleVoice&audioType=t2s&msg=Your OTP Code is 1234&msgType=text&mobile=99999999xx,9999999xxx&reDial=2&redialInterval=5&format=json
- **Benefits**:
  - Automate voice OTPs, alerts, or promotional messages.
  - Integrate with your systems for seamless communication.
  - Fetch real-time reports to monitor campaign performance.

**SMSGatewayCenter**’s Voice Call API offers a flexible solution for [automating voice campaigns](https://www.smsgatewaycenter.com). For assistance, contact our support team.

### More Related Articles

- [Is the Voice OTP API secure?](https://www.smsgatewaycenter.com/blog/kb/is-the-voice-otp-api-secure/)
- [How does the system handle failed deliveries?](https://www.smsgatewaycenter.com/blog/kb/how-does-the-system-handle-failed-deliveries/)
- [How can I test the Voice OTP API?](https://www.smsgatewaycenter.com/blog/kb/how-can-i-test-the-voice-otp-api/)

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