One very important feature of the Hubtel SMS Messaging API is its ability to allow developers to schedule SMS messages from their application. This allows you to schedule reminders within your app or send messages at a later time.

To schedule a message to be sent at a later time you simply set the time parameter of the Send SMS API request parameters. You must note that the message time will be converted to UTC (GMT +0.00) according to the time zone you have set on your portal account. Timestamps will however be reported in UTC. Scheduled message are not billed immediately and will always return with a zero rate.

POST /v1/messages HTTP/1.1
Accept: application/json
Authorization: Basic aWlocGtoZHU6bnZtdnp2bWY=

    "From": "Hubtel", 
    "To": "+233248183797", 
    "Content": "hello, world!",
    "RegisteredDelivery": "true",
    "Time": "2018-02-01 10:00:00"

Refer to full API reference