You can integrate sequential dialing using a Dial XML in which you can add a list of phone numbers or endpoints or a combination of numbers & endpoints so that the calls can be sequential for each recipient one after the other. 


The below example calls out sequentially to a list with two numbers. The first call will be to the number: 18217654321 with a timeout value of 30secs, If the call is not answered by 18217654321 then the call will be the call will be redirected to the second number 15671234567.


Note: You can combine endpoints and phone numbers in the XML.


Example: 1

<Response>
    <Dial timeout="30" action="http://foo.com/dial_action/">
        <Number>18217654321</Number>
    </Dial>
    <Dial>
        <Number>15671234567</Number>
    </Dial>
</Response>


The below example calls out sequentially to a list containing one number and one endpoint. The first call will be to the number: 18217654321 with a timeout value of 30secs, If the call is not answered by 18217654321 then the call will be the call will be redirected to the endpoint: sip:john1234@phone.plivo.com.


Example: 2


<Response>
    <Dial timeout="30" action="http://foo.com/dial_action/">
        <Number>18217654321</Number>
    </Dial>
    <Dial>
        <User>sip:john1234@phone.plivo.com</User>
    </Dial>
</Response>