The SparkPost SMTP API provides an SMTP relay service with features that are available through the X-MSYS-API custom header. It allows you to specify a campaign id, metadata, tags, IP pool, CC, BCC, archive recipient lists and more. SparkPost provides a cloud email platform that is built on AWS.
The following is a list of SDKs from our SDK directory that matched your search term. Though your definition of an SDK may differ, in our world, we define SDKs as platform- specific tools for consuming existing APIs of the sort we list in our API directory. For example, the Ruby SDK for consuming the Twitter Ads API. If you think an SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.