At the beginning of this week, Anthropic introduced a web search feature for its AI-powered chatbot platform, Claude. This new feature brings Claude up to speed with many of its competitors. Initially, it was unclear which search index was powering this feature, with one possibility being that Anthropic had developed its own search index. However, evidence now suggests that the search engine is actually Brave Search, which is maintained by the browser developer Brave.

The discovery was made by software engineer Antonio Zugaldia on Friday, who noticed that Anthropic had added “Brave Search” to its list of subprocessors in the documentation. This list includes all of Anthropic’s partners that process data for Claude. Furthermore, British programmer Simon Willison reported that he found identical search results on both Claude and Brave. Additionally, Willison discovered a parameter called “BraveSearchParams” within Claude’s web search function.

We have reached out to Anthropic for confirmation and will update this post if we receive a response.

It’s worth noting that Brave also powers the search functionality of another chatbot, Mistral’s Le Chat. In February, Brave and Mistral announced that Le Chat would be using Brave’s search API to provide live web results.

Some companies in the AI industry tend to keep their search index partnerships private, possibly due to competitive reasons. For instance, OpenAI has a partnership with Bing, but also uses other undisclosed sources to power the search experience in ChatGPT.