Should I use this call or the Omnichannel API?
This SMS API checks whether a phone number has opted out automatically prior to sending an SMS and therefore is good for marketing SMS messages.
For transactional SMS messages we recommend using our Omnichannel messaging API as it is more featured, omnichannel capable via a single call and allows batch message submissions.
This method sends a single SMS message to a contact's mobile number.
If you want, you can send long SMS messages (greater than 160 characters), but these will incur extra costs as they count as multiple messages.
You can send an unlimited number of SMS messages through the API, and this method doesn't add to your allotted total calls per hour.