The ActiveCampaign Node.js Sample Code by ActiveCampaign demonstrates how to include a reseller feature by testing API credentials, updating settings, returning whitelisted domains, and return saved events. Lines of code available for resellers show how to obtain available account plans.
Guerilla Mail is a simple idea with one purpose: to avoid spam. The idea is dead simple: go to the website, it gives you a random e-mail address that's good for one hour, and links to nothing else. Register for sites or whatever with it, and then never worry about it again. Although the web service is convenient, sometimes it's not everything you need. For those cases, one might want to look into using the Guerilla Mail API.
Email doesn't need postage, right? Is that old hoax about the postal service charging per message finally coming true? Not really. But PostageApp may be a service worth paying for if you want to send email from your application.
Newsweaver, communications software provider, offers the Newsweaver API, aimed at increasing intra-company or customer engagement through email campaigns. Newsweaver's platform utilizes homegrown microsite, segmentation, personalisation, in-depth reporting, and social media to encourage and increase engagement.