Project xCloud was first teased in 2018 and more flesh has been added to its bones since then, not least during E3 2019 where it was playable outside of Microsoft for the first time.
Here is everything you need to know about the Xbox cloud games service, including what devices will be compatible and when you might be able to try it out.
What is Project xCloud?
It is a streaming service, in that all games will be hosted on remote servers and live gameplay video will be sent to a compatible device over the internet. In return, controller codes are sent in the other direction so, for all intents and purposes, it feels like you are playing a game loaded on the device itself, whether it be a smart TV, PC, tablet or smartphone.
It is not a new idea; PlayStation Now already offers a similar experience on PS4 consoles, while Nvidia is back into the beta testing phase of its GeForce Now service. Google too will launch its own cloud gaming platform this year, Stadia. However, Microsoft believes it has a distinct advantage over the others as it promises to utilise its vast library of over 3,000 Xbox and PC games.
It also has one of the largest network of data centres around the world.
This, combined with the company's Azure cloud server network, will ensure that game requests can be served locally rather than across continents, potentially reducing latency by shortening the distance between the end user and the data centre.
Latency is the enemy of cloud gaming, often adding many milliseconds between button presses and actions performed on screen. And, while that doesn't sound like much, milliseconds are vital when it comes to gaming. Say you press the button to shoot an onrushing enemy, a few milliseconds of latency can be the difference between hitting them and not. Or, in a driving game such as Forza Horizon 4, the difference between successfully drifting around a corner or ending up wrapped around a tree.
If Microsoft can dramatically reduce latency in comparison to cloud gaming services we've tested before, it could be onto a winner.
Does that mean my Xbox One or other games console will be defunct?
Project xCloud is not designed to replace existing or future games consoles. Microsoft believes that it will be a different kind of service that caters for a different kind of user.
For starters, while it will likely be accessible through the Xbox One family of machines (plus Scarlett), xCloud will also be available on phones, tablets, set-top-boxes, TVs, etc. Basically, anything that has a screen and an internet connection.
"We’re developing Project xCloud not as a replacement for game consoles, but as a way to provide the same choice and versatility that lovers of music and video enjoy today. We’re adding more ways to play Xbox games," said Microsoft's CVP of cloud gaming, Kareen Choudry in March 2019.
"[It] will also open the world of Xbox to those who may not otherwise own traditional, dedicated gaming hardware. True console-quality gaming will become available on mobile devices, providing the 2 billion-plus gamers around the world a new gateway to previously console- and PC-exclusive content."
What games will be available?
At the beginning, Microsoft said it plans to host hundreds of Xbox games - referring to current and archive titles from its Xbox One and Xbox 360 line-ups. Maybe even a few original Xbox games.
However, it has since added that it has the technical ability to stream many more games from the back catalogues of its three generations of consoles. Unlike with Google Stadia, developers don't actually have to alter or adapt their games to work. If they already work on an Xbox One, they will work on xCloud: "Project xCloud has the technical capability to stream more than 3,500 games, without any changes or modifications required by a developer," said Xbox's Major Nelson in a blog posting.
"In other words, developers will be able to dramatically scale their existing games across devices, with no additional development, no additional code base maintenance and no separate updates. When a developer updates the Xbox One version of their title, those updates will also apply to all versions available on Project xCloud without any additional work."
In addition to existing games, there are more than 1,900 others in development for Xbox One - all of which have the potential to be on xCloud too.
When will I be able to use Project xCloud?
Project xCloud will officially launch in October. Microsoft will start by hosting open beta trials around that time.
Its employees are already using the platform in alpha test mode, as part of Microsoft's "take home" program. While, the company also first let the public try xCloud during E3 2019.
But everyone else should be able to get access from October. Xbox boss Phil Spencer revealed in an E3 2019 interview that it will launch alongside a new Console Streaming feature.
"We have two things coming this October, we've got our data centres with the blades in there, so you can access Xboxes we have and able to play games from there," he said.
"Or, if you already have an Xbox One or buying one this holiday, you are going to be able to turn that into a server that you can access on your phone wherever you go.
"Both of those things will be launching in October."
You can read more about Console Streaming below.
How much will xCloud cost?
This is the million dollar question and we hope the answer isn't exactly that.
Project xCloud will almost certainly be a subscription service eventually - possibly not at the public trial stage - but an actual price is a long way off.
Sony's rival service, PlayStation Now, currently costs £12.99 per month in the UK, but that allows downloads too, so might be a little steep for a streaming service alone. A better indication might be Google Stadia, which is also coming later this year. It will cost £8.99 per month for a Stadia Pro subscription and we expect Microsoft's alternative to be in the same ballpark.
Xbox Game Pass, the all-you-can-eat digital download service for Xbox One is £7.99 per month.
What devices will it be available for?
We don't yet know the exact list of devices that could support xCloud but Inside Xbox has shown it running on an Android phone linked to an Xbox One controller.
Apple revealed during its WWDC 2019 keynote that the Xbox One controller will be made compatible with iOS devices too, come the release of iOS 13. However, it is not yet know if it plans to allow Microsoft to release xCloud on the App Store - it has turned down similar cloud gaming platforms in the past.
In terms of other controls, Microsoft has said that on-screen touch controls will be developed for games, so that's one way of providing the experience on other devices too, but we're not that keen on the idea of trying to navigate through a hardcore session of Call of Duty: Black Ops 4 using touch.
The company is dabbling with its own Nintendo Switch-style clip-on controller concepts, as detailed in a filed patent and leaked internal document, so they might be available to smartphone and tablet owners in future.
Other than those, it is thought that Project xCloud access will be provided through TVs and set-top-boxes too, such as Samsung and LG smart TVs and Android TV boxes.
What is Console Streaming?
One interesting new development announced during E3 2019 is that a "Console Streaming" dual-service will be offered by Microsoft alongside xCloud.
Using the same technology, gamers will be able to use their own Xbox One consoles as an xCloud server and therefore stream their own games to a portable device.
PlayStation offers something similar in the form of PS4 Remote Play, but Xbox Console Streaming is different as you won't be restricted to having to be on the same home network. It will be available anywhere you have an online connection.
As we say above, it will be launching in October as part of an Xbox One system update, alongside xCloud itself.