Sitecore’s licensing model has evolved over the years, with variations on production vs non-production servers, domains, users, support and other factors. However, these were merely tweaks to a long-standing “perpetual” model. With the advent of the “consumption” model, the concept changes significantly.
In a perpetual model, you license the number of instances you can run. There’s a shifting formula for the number of management vs delivery instances, and the number of “non-production” (development, test, processing, reporting) instances that are allowed along with the licensed “production” instances. The number of concurrent logged-in users (content management users, not site visitors) is scaled by the number of instances purchased. The calculus changes over time, so it’s best to consult a Sitecore rep for the current terms. With this model, you own the licenses “perpetually”. You own the rights to the license perpetually. Support may be dropped after a period of time, and an annual maintenance agreement is needed for unfettered access to version upgrades, but you can continue running your solution as purchased, forever.
Fit for consumption
In the consumption model, there’s no restriction on the number of servers you can deploy (though there are still restrictions on non-production servers). Your license is purchased in “bands” of visits; in other words, you buy a range of anticipated activity. When you exceed this activity, you pay an overage, or decide it’s appropriate to increase your consumption band. Rather than perpetually license servers that may only be needed during peak traffic, the consumption model allows you to absorb peaks in traffic without a perpetual commitment. In a world where cloud servers can be spun up and down on demand, this license model is quite attractive.
There are some similarities in the models. There are restrictions on the number of concurrent CM users, and the number of non-production instances is capped. The definition of “non production” can be elusive in the perpetual model (again, consult a Sitecore rep), but in the subscription model it’s simplified. It’s literally the number of servers in production, including all roles for the edition you licensed.
Emerging technologies such as SXA and JSS are not automatically included in perpetual licenses – remember, in broad terms, you licensed the product perpetually, in the state it was in at the time. To take advantage of these technologies, you’d need to convert to a subscription license.
And if that’s not complicated enough, there’re different editions of Sitecore. XM (Experience Management) is a “content management only” edition, XP (Experience Platform) includes marketing automation, analytics, personalization etc, and XC (Experience Commerce), which provides a fully-integrated, micro-service based enterprise commerce platform. There are additional “add ons” for supporting email, print, federated experiences, social, and other optional features.