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Via the Voice API of sms77 you can issue calls to certain phone numbers. The simplest way is to specify a text which is read to the recipient via our text-to-speech Gateway. For advanced applications, you have the option of sending the text in XML format.

Please use the following URL for your request: https://gateway.sms77.io/api/voice

The following parameters are required in addition to authentication:

Required parameters

Parameter Description Possible values
to The recipient number.
Allowed are numbers and address entries (contacts only). Currently just one recipient per call is possible.
text The text message to be read or XML data. The input length may not exceed 10,000 characters. Dear customer. Your new glasses have just arrived. Please stop by to pick them up. Sincerely, your optician.

Optional parameters

0 = The parameter is deactivated – this is the default setting if not specified otherwise.
1 = The parameter is activated.

Parameter Description Possible values
debug If activated, no calls will be made or calculated. Useful to see if the connection to API actually works or not. 0
from The caller ID. Please use only verified sender IDs, one of your virtual inbound numbers or one of our shared virtual numbers. 491771783130
json If activated, the returned response is of JSON format and more detailed. 0
xml Specifies whether the text parameter is plain text or of XML format. 0 = text
1 = XML



The phone number +49171999999999 is called and This text is read. is announced on the phone.

Our Voice Gateway can be expanded individually – e.g. with interactive menus, MP3s can be played and much more. Contact us for your specific requirements!

Response Examples

Plain text

The API returns a plain text response by default.
The first row presents the response code.
The second row is the message ID.
The last row is the total price of the call.



The API returns a detailed JSON object with the parameter json set to 1.

  "success": "100",
  "total_price": 0.07,
  "balance": 45.678,
  "debug": false,
  "messages": [
      "id": "123456789",
      "sender": "491771783130",
      "recipient": "491716992343",
      "text": "Hi Sam, I am just calling to tell you that I am so in love with you!",
      "price": 0.07,
      "success": true,
      "error": null,
      "error_text": null


Setup a webhook of event_type: voice_status to receive real-time status updates of your call.

We will send the following parameters to your callback URL:

Parameter Description
callerId The caller ID which has been sent
duration You will get the duration of the call in seconds when it is completed
id The ID of the Voice Call
pricePerMinute The price per minute in Euro
recipient The recipient number
status The current status of the call
Possible values are: completed, no-answer, failed, initiated, ringing, in-progress