There are two distinct stages an inbound message will go through:

1. Received

Plivo will receive an inbound message from a carrier. The user will be charged for the inbound message.

If the message_url or message_method is not configured in the user’s application to which the number that receives the message is attached, the message remains in this state.

2. Delivered/Undelivered

Once Plivo receives the message, it sends a callback to the message_url. Based on the response Plivo gets, the next state of message is decided:

2-1 delivered: the message_url is valid and active. After sending a callback to the message_url, the state of message is set as ‘delivered’.

2-2 undelivered: the message_url is invalid, inactive or not responding. Plivo will retry callbacks for the next 24 hours. Retry interval is 5 minutes during the first hour and an hour for the rest of 23 hours. If all callbacks fail, the status of message will be set as ‘undelivered’.