How to automate contextual advertising?

Question

contextual advertising

Tell me please. There are IM in 60 thousand goods.
IM is integrated with the warehouse balance system, some of the goods constantly change status - that is, in stock / out of stock (depending on stock availability) 2. How large IMs
automate contextual advertising (I constantly see large industry players in the search results for NC requests. I am sure that they do not create ads manually)

Answer 1

Automate - only through a separate module that will pull the API. The big stores do this.
Or perhaps there are SaaS services, but online stores are individual.