Subscription Message Credits
Your plan includes a standard amount of message credits that reset every time you enter a new month into your subscription and any unused credits will not roll over.
For example: Our Pro Plan includes a standard total of 750 message credits monthly, but if you only used 690 of your credits and your next monthly subscription rolled in, you would only see your new 750 credits because the remaining 60 credits did not roll over.
Additional Purchased Message Credits
On the other hand, if you purchased extra message credits, those do not expire and roll over each time until they are completely used.
Here's an example: Let's say you bought an extra 400 credits because you were running a campaign and were close to using your monthly standard messages. If you only used 100 of those extra credits, 300 of those purchased credits would still be available for you until they were completely used since they do not expire.
Outbound and Incoming texts
Each outgoing and incoming text counts as a message credit. One outbound text is 160 characters and a text with more characters will cost an additional message credit. There's an indicator in the text box of how many message credits your text will use.
Add Message Credits
You can add message credits to your account through your account settings and you can automatically refill your credits if your balance is running low by enabling the Auto-Recharge feature.