SparkPost is a predictive email intelligence platform. weMail has integration with SparkPost. So you can use SparkPost as a gateway to send emails.
How to Configure
First, create an account on SparkPost.
Next, go to Settings→API Keys.
Click on Create API key and your API key will be generated. Copy the API key.
Go to weMail→Settings→Email.
Enable SparkPost and paste the API key. Then hit the Save Changes button. You are good to go.
Check out this detailed documentation on how to create the SparkPost API key.