The Postmark PHP SDK by Wildbit allows API interaction with the aim to simplify email communication. References include guides for installation and API calls. A sample displays how to send a first email from the app.
Message Bus is a cloud-native application service for email and mobile messaging. The selling point is the high deliverability rate, its ability to scale according to demand and the fact that it's simple enough to be used by developers with limited time and resources. The Message Bus API makes it possible for developers to easily add messaging functionality to their websites and apps.
Google has announced the upcoming shutdown of Google App Maker. Google App Maker is a low-code, G Suite development tool that allows businesses to fill gaps in their business workflows and operations. Google has cited "low usage" as the primary reason for shutting down the tool.