Yes, as it 's "just" SSE, this works pretty well behind Cloudflare and other similar solutions. Mercure also automatically sends the NGINX-specific headers required to allow unbuffered connections.

Native mobile apps are also entirely supported. It's a very common use case. Most mobile languages have SSE client libraries.

These are the key questions.

The biggest issue with SSE is that there is unfortunately alot of deployed software that will downgrade incoming connections to HTTP/1.1 so even if the client would have otherwise supported HTTP/2 or higher its not presented the ability to do so.