IndexNow
IndexNow is a procedure by which a website reports new or changed addresses to search engines immediately, instead of waiting for a crawler to come round. Bing, Yandex, Seznam and others take part — Google does not.
Technically it could hardly be simpler: the site sends the changed address together with a key to a collection point, and the participating search engines pick it up from there. One call, no waiting, no work for the business.
It helps most where currency counts: a promotion page, a changed opening time, a new job posting. Instead of days until a crawler next comes by, it takes minutes.
The caveat is the most important part: Google does not take part in this procedure. So if you hear "our changes are on Google instantly", it is worth asking. For Google the always-current sitemap and ordinary crawling still do the work.