Sparkpost is an SaaS service for E-Mail delivery and E-Mail templating that can be used to send E-Mails by calling an API.
In a lot of projects, it is a typical requirement that different E-Mails need to be sent and that the project stakeholders want to adjust E-Mail templates and content on a relatively regular basis.
Also, (mass) sending E-Mails and avoiding that they are classified as Spam is not an easy topic. That's why we decided to use E-Mail delivery services in our projects and evaluated different providers.
We decided to start using SparkPost because of pricing, feature set and the available reviews on the Internet. There are also other possible solutions such as SendGrid or Postmark.