Share code between client and server using WebAssembly[1]. The Twitch video player is written in C++ via WASM[2]. C# can be "full stack" with Blazor[3]. Rust can be "full stack" with Yew[4]. Similar support exists for other languages including Go[5] and even the TypeScript-syntax AssemblyScript[6].

[1]: https://medium.com/wasm/webassembly-on-the-server-side-c584f... [2]: https://news.ycombinator.com/item?id=16835769 [3]: https://dotnet.microsoft.com/apps/aspnet/web-apps/blazor [4]: https://github.com/yewstack/yew [5]: https://github.com/hexops/vecty [6]: https://www.assemblyscript.org/