Does anyone know if it is possible to batch send SMS messages with SendGrid? Their email service allows substitution and dynamic elements etc so you can send up to 1000 emails at a time. According to the documentation for the SMS service (https://www.twilio.com/docs/sms/api/message-resource#create-a-message-resource) all the examples appear to be single send instead.
You can bulk send SMS messages using Twilio Notify, however all the messages will have the same content and there is not substitution available. If you want to send different messages to your users, you will need to make an API request for each message.