What is YandexCalendar? Yandex's on-request crawler

None of the 1662 major websites we measure block YandexCalendar in robots.txt. 0 of those sites name it directly in their robots.txt; the rest are covered by a wildcard rule.

Key facts

What blocking YandexCalendar does

Yandex says this robot does not take the general robots.txt rules into account, including a User-agent: Yandex group; only a group that names it applies. The figures below count it that way.

How to allow or block YandexCalendar

Add one of these groups to the robots.txt file at the root of your domain. It is a stated preference that well-behaved crawlers read, not an enforcement mechanism.

User-agent: YandexCalendar
Disallow: /

User-agent: YandexCalendar
Allow: /

YandexCalendar user agent string

Yandex's page doesn't list a full string, so look for YandexCalendar in the user agent field of your logs.

How to verify a request is really YandexCalendar

Anyone can put a crawler's name in a user agent string, so the name alone proves nothing. We did not find a published IP list or reverse DNS rule from Yandex.

How to whitelist YandexCalendar in a firewall or CDN

robots.txt only states a preference. A firewall, CDN or bot protection service can still refuse the request, and the crawler then gets an error even though robots.txt allows it.

1. Check that no group in your robots.txt blocks it, using the rule above.
2. Add an allow rule in your firewall or CDN that matches the name in the user agent. Keep the rule narrow, because anyone can copy a name.
3. Check your server logs for a 200 response from YandexCalendar afterwards.

On Cloudflare, also check AI Crawler and Agent access policies, which can block search, agent and training traffic across a site.

Why YandexCalendar gets a 403 or 405 error

A 403 means the server refused the request, which usually points to a firewall or bot rule. A 405 means the server refused the request's method, so check any rule that only permits certain methods. A crawler that obeys robots.txt won't request a page it is told to avoid, so an error in your logs points to your server's configuration. To stop it deliberately at the server, this nginx rule returns a 403:

if ($http_user_agent ~* "YandexCalendar") {
    return 403;
}

Who blocks YandexCalendar, by sector

Other Yandex crawlers

YandexBot (search indexing), YandexImages (image indexing), YandexVideo (video indexing), YandexMedia (multimedia indexing), YandexBlogs (blog search), YandexMarket (Yandex Market), YandexAdNet (advertising network), YandexOntoDB (information cards), YandexPagechecker (structured data checks), YandexSitelinks (sitelinks checks), YandexSpravBot (Yandex Business), YandexVertis (search verticals), YandexVerticals (classifieds verticals), YandexWebmaster (Yandex Webmaster), YandexImageResizer (mobile images), YandexAccessibilityBot (page accessibility checks), YandexCheckBot (availability checks), YandexDirectDyn (dynamic ad banners), YandexDirect (ad matching), YandexFavicons (favicons), YandexFeed (submitted structured data), YandexMobileBot (mobile layout checks), YandexMobileScreenShotBot (mobile screenshots), YandexOntoDBAPI (information card data), YandexPartner (partner sites), YandexRCA (previews), YandexSearchShop (product catalogues on request), YandexTracker (Yandex Tracker), YandexUserproxy (user actions), YandexVideoParser (video indexing), YandexScreenshotBot (screenshots).

See all 36 AI crawlers, the rule change log or the full study. Being reachable is only the first step: how AI search engines choose what to cite covers the rest.

IndexHalo. "YandexCalendar block rate across major websites." Measured 12 November 2026. https://www.indexhalo.com/ai-crawlers/yandexcalendar/

<a href="https://www.indexhalo.com/ai-crawlers/yandexcalendar/">YandexCalendar block rate across major websites, IndexHalo</a>