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Set up an Anonymous Voice Session

This page shows you how to set up a session where two users can speak to each other using an assigned masking ID instead of their phone numbers. You must have the Anonymous SMS API enabled.

This is part of the larger procedure described on Set up Anonymous 2-way Voice with TeleSign’s Voice API .

Reference Page

POST /anonymous/session/sms_voice


TeleSign calls have a maximum call duration of four hours.

Supported Codecs

Use only codecs and standards for audio files supported by the Voice API. See Supported Standards and Codecs for more details.

How It Works

To connect two users without either knowing the other’s true phone number using a session, the flow works like this:

  1. You receive a request for communication from an end user wanting to speak with another end user (say a rider wants to call the driver in a taxi app).
  2. You create a session request and send it to TeleSign. Your request will include the phone numbers of both parties.
  3. The rider initiates their call. This call request is routed to TeleSign’s servers.
  4. TeleSign receives the call request and connects the call to the driver. Both the sender ID of the rider and the sender ID of the driver are masked from each other.

General Requirements

Request Requirements

  • Authentication: Basic (easiest to implement) or Digest
  • Endpoint: https://rest-ww.telesign.com/v1/anonymous/session/sms_voice
  • Encoding: Accepts only UTF-8 unicode characters as inputs.
  • MIME Type: application/json
  • Required Headers: Content-Type - application/json

Response Details

  • MIME Type: application/json


Example 1: Create Session

POST https://rest-ww.telesign.com/v1/anonymous/session/sms_voice HTTP/1.1
Authorization: Basic 12345678-9ABC-DEF0-1234-56789ABCDEF0:vjE/ZDfPvDkuGNsuqCFFO4neYIs=
Content-Type: application/json; charset=utf-8

   "phone_number_1": "15555551212", 
   "phone_number_2": "15558675309",
   "validity_period": 500
Response Body
  "reference_id": "C5B8F46B7D2C016C88308ABCE1D00169",
  "session_data": {
    "message": "",
    "phone_number_1": {
      "complete_phone_number": "15555551212",
      "country_code": "1",
      "country_iso2": "US",
      "country_iso3": "USA",
      "country_name": "United States",
      "masked_id": "16467740233"
    "phone_number_2": {
      "complete_phone_number": "15558675309",
      "country_code": "1",
      "country_iso2": "US",
      "country_iso3": "USA",
      "country_name": "United States",
      "masked_id": "16467740234"
    "resource": "sms_voice",
    "session_end_on": "2018-03-05 10:59:13.761245",
    "validity": 500
  "status": {
    "code": 2700,
    "description": "Session successfully created",
    "updated_on": "2018-02-12T14:57:11.765723Z"

Next Steps

Check out these related pages: