IFTTT

If This Then That (commonly known as IFTTT, ) is a service that allows a user to program a response to events in the world of various kinds. There is a long list of kinds of events to which IFTTT can respond, all detectable via the Internet. An example event is that Weather Underground reports rain is forecast for tomorrow. Another is that someone tagged the user in a photo on Facebook. There is similarly a long list of kinds of responses that are possible, all executable via the Internet. An example response would be to send an email to the user saying rain is forecast or copy the aforementioned photo to the user's archive.
IFTTT has partnerships with hundreds of service providers that supply event notifications to IFTTT and execute commands that implement the responses, but some event and command interfaces are just public APIs.
The programs, called applets, are simple and created graphically.
User can create programs and otherwise control IFTTT with a web interface or iOS or Android application. 
History.
On December 14, 2010, Linden Tibbets, the co-founder of IFTTT, posted a blog post titled “ifttt the beginning...” on the IFTTT website, announcing the new project. The first IFTTT applications were designed and developed by Tibbets and co-founder Jesse Tane and the product officially launched on September 7, 2011.
By April 2012, users had created one million tasks. In June 2012, the service entered the Internet of Things space by integrating with Belkin Wemo devices, allowing applets to interact with the physical world. In July 2013, IFTTT released an iPhone app and later released a version for iPad and iPod touch. Then in April 2014, an Android version came out. By the end of 2014, the IFTTT business was valued at approximately US$170 million.
On February 19, 2015, IFTTT launched three new applications. Do Button triggers an action when you press it. Do Camera automatically uploads the image to the service of your choice (Facebook, Twitter, Dropbox, etc). Do Notes does the same as Do Camera except with notes instead of images. In November 2016, the four apps were merged. By December 2016, the company announced a partnership with JotForm to integrate an applet to create actions in other applications.
Part of the revenue of IFTTT comes from "IFTTT Platform" partners, who pay to have their products connected to the service.
On September 10, 2020, the service switched to a limited freemium model with a subscription-based version known as "IFTTT Pro", which allows services to use conditional statements and query data for more complex tasks. At the same time, all existing users were limited to three custom applets, being required to subscribe to Pro in order to remove this limitation. This decision generated criticism from IFTTT's community of users.
Features.
Overview.
IFTTT employs the following concepts:
Reception.
IFTTT has been received positively by "Forbes", "Time", "Wired", "The New York Times", and "Reader's Digest". Microsoft developed a similar product called Microsoft Flow (later renamed Microsoft Power Automate).