This library written in Ruby provides a Ruby wrapper for the SendGrid Newsletter API. SendGrid's Newsletter API allows users to access data and interact with the newsletter app portion of the SendGrid product.
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.
A little less than a year after launching a private beta of the UK government's notification platform, GDS has upgraded to v2 of the associated API. GOV.UK Notify is a service that allows the government to text, email, and send letters to citizens and track the progress of such notifications.