Every Twilio SMS or MMS message request has a status value which describes the current state of the message. Here are the most common message statuses, and their meanings.

Outbound Message Status Progression

When sending outbound messages with the REST API, this is a typical sequence of status values:

Queued Twilio has received your request to create the message. All new messages sent from a specific Twilio phone number are created with a status of queued.
Accepted Twilio has received your request to create the message from a Messaging Service. Twilio is determining the optimal ‘From’ number from your service.
Sending Twilio is forwarding your message request to one of our Super Network partners.
Sent Twilio has received a confirmation from our Super Network partner advising they have accepted the message.