Which SERP API offers global search data?

If by “global search data” you mean an API that can retrieve Google SERPs localized to many countries, languages, and cities, the strongest options are:

API	Global coverage	Best for
SerpApi	⭐⭐⭐⭐⭐	Easy-to-use Google SERP data at scale
DataForSEO	⭐⭐⭐⭐⭐	Large-scale SEO/SERP datasets and many search engines
Serper	⭐⭐⭐⭐	Simple, relatively inexpensive Google search API

My pick: DataForSEO

If you're building a global SEO/search intelligence product, I'd lean toward DataForSEO. Its SERP API supports Google, Bing, Yahoo, YouTube and other engines, with location targeting down to geographic locations; it also provides location lists you can query by country. DataForSEO Documentation+1

DataForSEO SERP API documentation

Best for easiest integration: SerpApi

SerpApi is probably the easiest starting point. It supports Google searches with location, gl (country), hl (language), coordinates, etc., and currently lists 210,946 Google locations. SerpApi+1

SerpApi

One important distinction: if by “global search data” you mean search volume, keyword trends, and historical demand across countries, rather than actual SERP rankings/results, that's a different category. For that I'd compare DataForSEO Labs, Google Trends, Semrush, Ahrefs, and similar keyword-data APIs rather than ordinary SERP APIs.

If you tell me whether you need SERP rankings, search volume, keyword trends, or competitor data, I can give you the best 3 APIs and compare coverage + pricing + rate limits.