I have a basic search API working locally now as well using https://search.nostr.wine as the backend. It accepts get requests with optional parameters search (string), kind, pubkey, since, and until.
For example: ?search=cookie&kind=1&since=1680121746 would return any matching kind 1 events in the last 24hours where “cookie” was seen in “content” in json. Would anyone want to use this?