Creating a query syntax for aggregating search results would be pretty amazing. There is another project posted about yesterday they were talking about creating a mapping of nostr notes containing HTML. It could also parse markdown, since it has a hyperlinking scheme too.

Not sure about PHP though, I mean, it would work but such a clunky old language. Go is great for web servers and a KV store for making indexes, would be pretty small and fast and simple, and can run on every platform (even WebAssembly, inside a browser, if you stick to using websockets and http).