From their site: Put your clients back in the driving seat and let them create and send their own great looking emails in-house. Once you design a template for each client, they can easily add their own content, select their recipients and schedule delivery in their own time. The MailBuild API will allow you or your clients to perform a range of operations on their accounts, including the addition and removal of subscribers to their lists.
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.