In Installed Packages, create an API integration to get a client ID and client secret. Use these email permissions settings for the API integration: write, read, and send. Use these SMS permissions settings for the API integration: write, read, and send.
Never hard code client IDs or secrets in client side applications.
Set up a transactional email send definition. The send definition contains the message template and delivery configuration. Each request to send a transactional email message must include a reference to a send definition.
Create an optional subscription. A subscription uses a webhook to send you message analytics in real-time. Analytics data includes information about sends and bounces.
Set up a transactional SMS send definition. The send definition contains the message template and delivery configuration. Set up a definition for each messaging use case. For example, create one send definition for two-factor authentication messages and a separate one for order confirmations. Each request to send a transactional SMS message must include a reference to a send definition.
Create an optional subscription. A subscription uses a webhook to send you message analytics in real time. Analytics data includes information about which messages were sent or not sent.