How to make HTTP and HTTPS versions of the site available

A narrow but consequential case: a visitor’s device cannot open the HTTPS version of a site — Yandex’s own example is a certificate from the National Certification Centre that the device does not trust — and Yandex can offer that user the HTTP version instead. For it to be able to do so, three conditions must all hold.

The three conditions

• The HTTPS version is the primary address of the site.
• The HTTP version is reachable by users and by the Yandex bot — which means removing any redirect from HTTP to HTTPS. Verify with the server response check.
• The content of the HTTP version is completely identical to the HTTPS version.

Why this is worth understanding

It runs against standard practice everywhere else. The usual advice — redirect all HTTP traffic to HTTPS, permanently, with no exceptions — makes this fallback impossible. For a site serving audiences whose devices may not trust the certificate chain in use, that blanket redirect turns a degraded experience into no experience at all: the user sees a certificate error and leaves.

Who this actually applies to

Sites using certificates from certification authorities with limited device support, and audiences on older or restricted devices. For most international sites with a mainstream certificate, the standard redirect-everything approach remains correct, and this configuration would only create a duplicate address to manage.

The cost of enabling it

Two reachable versions of every page. That is a mirror situation by definition, so the primary address must be set explicitly and monitored, and the two versions must not drift apart in content. This is a deliberate trade — accessibility for a specific audience against configuration complexity — and it is only worth making when that audience actually exists.