Stadia is a cloud gaming service operated by Google. It is advertised to be capable of streaming video games up to 4K resolution at 60 frames per second with support for high-dynamic-range, to players via the company's numerous data centers across the globe, provided they are using a sufficiently high-speed internet connection. It is accessible through the Google Chrome web browser on desktop computers, Pixel smartphones, supported smartphones from Samsung, OnePlus, Razer and Asus, as well as Chrome OS tablets and Chromecast for TV support. Source: Wikipedia
The service is planned to be integrated with YouTube, and its "state share" feature will allow viewers of a Stadia stream to launch a game on the service on the same save state as the streamer. This has been used as a selling point for the service. It is compatible with HID class USB controllers, though a proprietary controller manufactured by Google with a direct Wi-Fi link to data centers is available alongside the service. Despite comparisons, Stadia is not similar to Netflix, in that Stadia requires users to purchase games to stream via Stadia rather than pay for access to a library of games. While the base service is free and requires users to purchase games, a Pro tier monthly subscription allows users to stream at higher rates of up to 4K resolution, surround sound, and offers 1-4 free games a month that the user has access to while they are subscribed to Pro with or without gaps. Both tiers allow users to play online multiplayer without any additional costs.
Known in development as Project Stream, the service was debuted through a closed beta running Assassin's Creed Odyssey in October 2018. Stadia was publicly released on November 19, 2019 in selected countries and received a mixed reception from reviewers. The service competes with Sony's PlayStation Now service, Nvidia's GeForce Now, and Microsoft's Project xCloud. On 8 April, 2020 Google started rolling out Stadia free base service, along with giving new users two months of Pro subscription.