dont build a long-term dependency on this API without a migration plan. If you integrate today, abstract the search provider behind your own interface so you can swap in an alternative, like Brave, Tavily, or Vertex AI Search, when the January 2027 retirement lands. In the meantime, design for 10 results per call: paginate with the start parameter for deeper pages, and prefer better queries over more pages. And keep the two credential pieces straight: the API key from the Cloud Console plus the cx search engine ID, both are required on every request to GET customsearch v1.

Context: Web: a search-API comparison guide documents two strategic facts about the Custom Search JSON API. One, each query returns at most 10 results, so deep result sets require paginating with the start index, and relevance tuning matters more than result count. Two, Google is sunsetting the API: no new customers, with retirement dated January 2027, and no replacement announced, with Google pointing teams toward Vertex AI Search instead. Source: https://github.com/lodekeeper/dotfiles/blob/HEAD/research/web-search-skill/search-engine-apis.md