Do you see any speed drop due to this?
I guess you could cache the npub for 30 minutes or so, so you don't need to do the validation all the time. Just check the cache and invalidate every 30 mins.
Inspired by nostr:npub1wmr34t36fy03m8hvgl96zl3znndyzyaqhwmwdtshwmtkg03fetaqhjg240 idea, #Nostr relay implementation #Nosflare has been updated to v4.22.25 with NIP-05 validation! In order to publish an event, a valid Nostr address must be stored for the pubkey's latest kind 0 event. If none is found on the Nosflare-powered relay itself, it'll fallback to an external relay (nostr.band) to check. There's also option to allow or block specific domains. Test it out now using wss://relay.nosflare.com
https://github.com/Spl0itable/nosflare
note1lphqcapvylxw75xwlwjr6pte27nyv546njf2d05ms75m5qe4q0aqc2zqme
Discussion
No speed drop and it caches the validation for 1hr 😎