Bing is Microsoft's search engine. Microsoft unveiled it on 28 May 2009 and rolled it out worldwide on 3 June 2009. Besides answering searches on bing.com, its index is the web source for Copilot, Microsoft's AI assistant.
Bing is Microsoft's search engine: how it finds and indexes pages, why its index also feeds Copilot, and what share of searches it has in Spain.
What Bing means
Bing is a brand, but in SEO the word usually refers to an index: the copy of the web that Microsoft fetches with its Bingbot crawler, stores and ranks. That index is used beyond bing.com. According to Microsoft's documentation on Copilot for businesses, Copilot and Copilot Chat send a query to the Bing search service when information from the web improves an answer. DuckDuckGo says in its help pages that it sources most of its traditional links and images from Bing.
Until August 2025, other companies could query that index through the Bing Search APIs. Microsoft retired them on 11 August 2025 and pointed customers to "Grounding with Bing Search", a feature of Azure AI Agents that lets an AI agent add current web data to its answers.
How it works
Bing's webmaster guidelines describe the usual search engine process: discover URLs, crawl them, index them and rank them. Bing discovers pages through links, XML sitemaps and IndexNow, a protocol a site uses to report that a URL is new, has changed or has been deleted. Apart from Bing, Amazon, Naver, Seznam.cz, Yandex and Yep accept IndexNow submissions. Submitting a URL does not guarantee that it is indexed right away.
To detect changes, Bing uses the lastmod date in the sitemap and HTTP headers such as ETag. The guidelines also state that robots.txt controls crawling, not indexing. To keep a URL out of Bing, Copilot and grounding results, it needs a noindex directive.
Two directives are specific to Bing and affect Copilot. According to the same guidelines, noarchive prevents content from being used in Copilot responses and grounding results, and nocache limits Copilot to the page's URL, title and snippet.
The path of a URL through Bing, and what a site can control at each point.
The way into the index
1
DiscoverBing discovers pages through links, XML sitemaps and IndexNow.
IndexNowreports that a URL is new, has changed or has been deleted. Submitting a URL does not guarantee that it is indexed right away.
2
CrawlBingbot fetches the URL. To detect changes, Bing uses lastmod and ETag.
robots.txtcontrols crawling, not indexing
3
Index and rankBing stores and ranks the page in its index.
What the index feeds
BingCopilotGrounding
noindexkeeps the URL out of Bing, Copilot and grounding results
noarchivecontent is not used in Copilot responses and grounding results
nocachelimits Copilot to the URL, title and snippet
The effect of robots.txt, noindex, noarchive and nocache is described in Bing's webmaster guidelines.
Being in Bing's index is a precondition for Copilot, not a green light.
Why it matters
In Spain, Bing is the second search engine by a wide margin. According to StatCounter, which measures visits on the sites in its network, Bing accounted for 3.5% of searches in September 2026, against 94% for Google, in rounded figures. The traffic that comes straight from bing.com is therefore small.
Bing's weight lies in what its index feeds. Its guidelines say that Bing search and Copilot search rely on the same crawling, indexing and ranking foundation. A page that Bing has not indexed cannot be cited in Copilot answers drawn from web search.
We checked this for zds.es on 14 October 2026. The robots.txt treats Bingbot like any other crawler, with a single block of rules. All 1,371 URLs in the sitemap carry a lastmod date, and the two pages we checked, the homepage and a glossary entry, use neither noarchive nor nocache.
Best practices
Add the site to Bing Webmaster Tools and submit the sitemap there.
Report new, changed and deleted URLs through IndexNow.
Keep the lastmod dates in the sitemap accurate.
Use noindex, not robots.txt, to keep a page out of Bing and Copilot.
Check that no template sets noarchive or nocache by accident.
Measure traffic from Bing and from Copilot separately.
Common mistakes
Writing Bing off because of its share in Spain without checking which services use its index.
Blocking Bingbot in robots.txt with rules copied from another site.
Assuming that IndexNow guarantees indexing.
Setting noarchive or nocache on content that should be citable.
Assuming that a page indexed by Google is also in Bing, without checking in Bing Webmaster Tools.
Manuel Riveiro RodriguezCEO & Digital Strategist
A technical audit covers this and everything else in one pass.
Microsoft. It unveiled Bing on 28 May 2009 and rolled it out worldwide on 3 June 2009. Today Microsoft also uses Bing as the web source for Copilot.
How are Bing and Copilot related?
According to Microsoft's documentation for businesses, when web information improves an answer, Copilot turns the question into a short search query and sends it to the Bing search service. Bing's guidelines say that both rely on the same crawling, indexing and ranking foundation, so a page that Bing has not indexed cannot be cited in Copilot answers drawn from web search.
Is Bing worth the effort when Google has over 93% of searches in Spain?
Direct traffic from Bing is small: about 3.5% of searches in Spain in September 2026, according to StatCounter. But its index also reaches Copilot and DuckDuckGo. Most of the work overlaps with SEO for Google. The Bing-specific steps are adding the site to Bing Webmaster Tools, using IndexNow and checking the noarchive and nocache directives.
How do I stop Copilot from using my site's content?
According to Bing's guidelines, noarchive prevents content from being used in Copilot responses and grounding results, and nocache limits Copilot to the URL, title and snippet. To keep a page out entirely, from both Bing and Copilot, it needs noindex. robots.txt only controls crawling.
Does the Bing search API still exist?
Not as a public product. Microsoft retired the Bing Search APIs on 11 August 2025. As a replacement it offers "Grounding with Bing Search" in Azure AI Agents, which lets an AI agent include current web data in its answers.
