How the Mentionable Index is built

The Mentionable Index lists the domains AI engines cite when they answer. It rests on 331,975 answers recorded from February 2026 to September 2026, across 8 engines, and publishes 12,378 domains today.

What counts as a citation

A citation is a link to a page that an AI engine attaches to its answer. It is in the text when the link appears inside the answer itself, and listed when it only shows up in the list of sources shown alongside. Citations are grouped by domain.

Where the data comes from

The figures come from the prompts tracked on Mentionable, the questions each market asks AI engines, run on a regular schedule across ChatGPT, Claude, Perplexity, Gemini, Copilot, Google AI Mode, and Google AI Overview.

Updates

Figures are recalculated every week. Latest data point included: September 15, 2026.

Citing the data

Index figures are published under the CC BY 4.0 license. You can reuse them, including commercially, as long as you cite the source: "Mentionable Index, mentionable.ai/index, September 2026".

Frequently asked questions

What is a citation in the Mentionable Index?

A link to a page that an AI engine attaches to its answer. It counts as in the text when it appears inside the answer, and as listed when it only shows up in the list of sources.

Why is a domain missing from the index?

AI engines have not cited it often enough yet in the answers tracked on Mentionable. It enters the index as soon as they do.

Can I reuse the index data?

Yes, under the CC BY 4.0 license, as long as you cite the Mentionable Index as the source along with the month of the data.