Definition
An AI Search Index is a web index built specifically to retrieve fresh, citable content for AI search answers, as distinct from a classic search engine index optimized for ranking a list of links. As AI assistants grow, providers including OpenAI and Meta are building their own AI search indexes rather than relying solely on traditional search backends.
The shift is visible in crawler behavior. Meta-WebIndexer went from about 2% to nearly 38% of tracked AI crawler requests between mid-July and August 2026, as documented in the Meta-WebIndexer report, which lines up with reports that Meta is building its own web search index. OpenAI's OAI-SearchBot is a citation crawler that feeds ChatGPT Search's own retrieval, distinct from GPTBot which is a training crawler.
For GEO and SEO teams, the rise of dedicated AI search indexes means crawler access and content legibility matter across more providers, not just Google and Bing. Ensure AI crawlers like OAI-SearchBot and Meta-WebIndexer can reach your content, monitor AI crawler logs for new crawlers, and verify crawler identity with AI crawler verification. The Meta-WebIndexer data and the Meta-WebIndexer bot page track this shift.
Treat AI search indexes as a growing set of retrieval surfaces, each with its own crawler and access rules, and ensure your content is crawlable and answer-ready across all of them.
Examples of AI Search Index
- A team uses the [Meta-WebIndexer report](/data/meta-web-indexer) to brief stakeholders that Meta is building its own AI search index.
- A site owner ensures [Meta-WebIndexer](/bots/meta-webindexer) and [OAI-SearchBot](/bots/oai-searchbot) can crawl its content after seeing their traffic rise.
- A GEO team monitors [AI crawler logs](/glossary/ai-crawler-logs) for new AI search index crawlers and updates robots.txt accordingly.
- A brand tracks citation share across ChatGPT, Perplexity, and emerging Meta AI search as the index landscape diversifies.
