Crawl-to-referral gap
The ratio between how often an AI engine reads a site and how many visitors that engine sends back, measured per engine.
Also called: traffic gap, crawl gap
The crawl-to-referral gap is how many times an engine reads your site for each visitor it returns. It is the clearest single number for what AI search has changed.
Why is this number worth tracking?
Traditional search was a trade: content in, traffic back. Analytics tools measure only the traffic half, so when the trade breaks, the dashboards show a slow decline with no visible cause. Measuring crawls alongside referrals makes the cause explicit.
What does a typical gap look like?
Traditional search engines often sit near five crawls per visitor returned. AI answer engines routinely exceed one hundred, and some return no measurable traffic at all. The contrast between the two, on the same site in the same month, is usually more persuasive than either number alone.
How is it measured?
Crawls are counted at the edge by identifying and verifying each bot. Referrals are counted by
classifying the referring source of human visits, including AI engines that pass a referrer. Both
are attributed to the same provider so GPTBot crawls and chatgpt.com visits appear on one row.
Does a large gap mean I should block the engine?
Not necessarily. A large gap means the exchange is one-sided, and blocking is only one response. Monetizing the crawl keeps you present in answers while restoring compensation.
What else should I read?
- AI crawler
A bot operated by an AI company that fetches web pages to train a model, build a search index, or answer a user's question in real time.
- Answer engine
A system that responds to a question with a synthesised answer rather than a list of links, typically by retrieving live web pages and summarising them.
- Share of answer
How often a brand appears in AI-generated answers across a fixed set of questions, measured relative to the competitors named in the same answers.