The in-development streaming app Rainway was announced back in March, but what you may not know is that the app fully intends to stream PC games in "super-high quality, with practically no lag" to your Nintendo Switch. Of course, this doesn't mean Nintendo ultimately plans to allow it, but as of right now the company has not taken public action to prevent Rainway from appearing on Switch or the Nintendo eShop.
Much of what we know about Rainway comes from its parent software's blog, which is admittedly simplistic. Still, both of the app's developers have active Twitter accounts, as does the app itself. The app's creator has also posted to Reddit stating his intentions, and there's little to suggest as of now that the app is fake or a hoax. The basics of what to expect are detailed below, from the aforementioned blog.
Rainway's signature feature is that it's available on any device with a web browser. You'll simply visit play.rainway.io, log in, and kick back with your favorite games. Native apps for Android, iOS, Nintendo Switch, Xbox, and other platforms are being developed to provide an even more seamless experience.
As mentioned, it remains to be seen if Nintendo will willingly play along with this, but theoretically a user could also just access Rainway via web browser even if its eShop app is eventually blocked (that is, assuming a Switch software update grants direct access to its web browser). Web apps like Plex work just fine with Wii U's browser, so there's little reason to believe Rainway's solution won't function similarly if needed. Still, I think we'd all prefer the native app to be approved, so cross your fingers.
You can check out Rainway's official site for more information, and there also appears to be a May 5th beta planned that you can preregister for. For now this is certainly a wait-and-see situation, but if Rainway even partially delivers what it's promising, it will be a step in the right direction.