Voice API

TeleSign’s Voice API is a powerful and flexible JSON-RPC API that allows you to build application-to-person, person-to-application, and person-to-person voice calling into web and mobile applications.


If you are interested in trying TeleSign’s Voice API, sign up by contacting our experts.

You can do many things with this API, such as:

  • Make, receive, and control calls - Programmatically control, make, receive, manage and route calls.
  • Lease phone numbers and set caller ID - Easily buy and use phone numbers across many countries (120+) to receive inbound calls and to establish end-user recognizable caller IDs for outbound calls.
  • Connect two parties - Design person-to-person calling experiences directly from an application to provide a two-way voice communications channel.
  • Deliver secure, voice-based one-time passcodes (OTPs) - Verify users and transactions in real-time, anywhere in the world using out-of-band voice messaging.
  • Collect digits (DTMF tones) - The ability to collect a series of DTMF digits during a phone call, prompting the user to take action, and immediately request returns.
  • Stream audio - Play your own audio files during an active phone call for voice greetings, call scripts, notifications, branding messages and more and utilize Amazon Polly for text-to-speech through lifelike voices in a variety of languages.
  • Text-to-speech with broad language support - Convert text into a voice-based message using text-to-speech (TTS). Provide a localized customer experience with TTS available in 26 languages & dialects (more than any competitive offering).
  • Build interactive voice response (IVR) flows - Build easy-to-manage Interactive Voice Response (IVR) flows with DTMF key prompts to send callers through pre-selected call flows to reduce support costs, call transfers, and agent handling times (by approx. 60-80%).
  • Number Masking - Use phone number masking to connect two parties without disclosing user identities, to maintain privacy and keep transactions “on-platform.”
  • Survey after call - Automatically send surveys after calls to collect feedback from customers or clients.
  • Record Calls - Record and retrieve recordings.
  • Advanced phone number cleansing - Properly formats phone number entered by end-user for more reliable and secure call delivery, which improves deliverability by more than 10% in most markets.
  • Traffic monitoring - TeleSign performs automated traffic monitoring to identify red flags and suspicious patterns, which helps protect businesses from International Revenue Share Fraud (IRSF) attacks.