It’s done and dusted. Since someday last month, everything Netflix does runs on Amazon Web Services, from streaming video to managing its employee and customer data.

In early January, whatever little bits of Netflix that were still running somewhere in a non-Amazon data center were shut down, Yuri Izrailevsky, the company’s VP of cloud and platform engineering, wrote in a blog post Thursday.

To be sure, most of Netflix had already been running in the cloud for some time, including all customer-facing applications. Netflix has been one of the big early adopters of AWS who famously went all-in with public cloud. Thursday’s announcement simply marks the completion of a seven-year process of transition from a data center-based infrastructure model to a 100-percent cloud one.

Read more: Cloud Reboot Causes Cold Sweat at Netflix

Those last bits to migrate were billing and customer and employee data management.

The reason? Scale. Netflix today has eight times more customers using its video streaming service than it did in 2008, when it started using AWS. The streaming application is also constantly changing as more and more features get added and relies on more and more data.

“Supporting such rapid growth would have been extremely difficult out of our own data centers; we simply could not have racked the servers fast enough,” Izrailevsky wrote.

In January, Netflix expanded to more than 130 countries, and AWS, with its global footprint, made it a lot easier to do.

Read more: Condé Nast Parts With Delaware Data Center in Favor of Amazon’s Cloud (VIDEO)

Cloud Changed the Way Netflix Runs the Company

It took seven years because Netflix didn’t simply take everything it had running in its data centers and replicate it on AWS (that would have been the easiest way to go). This was a seven-year fundamental transformation of the way the entire company runs, Izrailzevsky wrote, and it involved a lot of learning.

Instead of a big monolithic application, where every change is centrally coordinated, the new Netflix app is a series of micro-services, each of which can be changed independently. “Budget approvals, centralized release coordination and multi-week hardware provisioning cycles made way to continuous delivery, engineering teams making independent decisions using self-service tools in a loosely coupled DevOps environment, helping accelerate innovation,” he explained.

Cloud Lowers Cost for Netflix

Interestingly, Netflix found that its operating costs had actually gone down as a result of moving to AWS. You often hear that once a company reaches a certain scale, continuing to rely on public cloud becomes more expensive than building its own data centers.

But that wasn’t the case for Netflix, according to Izrailevsky, who said the company’s cloud cost per streaming start was a “fraction” of the cost of streaming from its own data centers. Its cost went down because of the flexibility of being able to constantly adjust the mix of cloud instances in use and to grow or shrink capacity as needed.

In other words, a monolithic data center where physical boxes take time to install, decommission, or upgrade, gave way to a fluid infrastructure that can be adjusted on the fly for more efficient utilization of resources.

More details about the final step in Netflix’s transition to the cloud in Izrailevsky’s blog post.