What does the Google Shopping API return?
There are three endpoints, each answering a different question. The search endpoint takes a query and returns up to 40 products a page with prices, matching what a shopper sees on Google Shopping. The product endpoint takes one product's identifier and returns its full detail: every seller offer, variants, specs, reviews and videos where Google shows them. The stores endpoint is the continuation for that same product's remaining sellers, for products with more offers than fit in one response.
All three return structured JSON rather than a rendered page, with the same locale controls: hl for interface language and gl for the country the ranking is computed against, so results reflect the market you're actually comparing prices in.