Do you redirect to the mobile version of the site users who came to the site from mobile devices at the main address?

Question

Web development

You have a website and a mobile version of the site.

1. Are you automatically redirecting mobile users to the mobile version?
   
2. How do you define mob. users?
   
3. Which devices are considered mobile and which are not?
   

Answer 1

Yandex has a convenient API for detection:
api.yandex.ru/detector/
The Yandex.Detector API provides the ability to determine the model and characteristics of a site user's mobile device using the headers of HTTP requests sent by the browser of their device.

Answer 2

Wikipedia sends to the mobile version, even if you go to the full version (I go from the IPhone). At the same time, at the end of the page there is an inscription "Go to the full version." If you click on it, the full version will be used for some time (most likely it depends on the lifetime of the cookies).

Answer 3

At the first visit, I ask which version to use: mobile or not. At the same time, on any page, the user has the opportunity to change the view.

Answer 4

1. Yes. And since part of the business is the creation of mobile versions of ready-made resources, there is also a redirect everywhere.
2. Checking the User-Agent header. The easiest way (but also the most full of holes):
<script src="http://cssuseragent.org/cssua.min.js" type="text/javascript"></script>
<script type="text/javascript">
if (cssua.userAgent.mobile)
document.location="http://wap.site.com/";
</script>
</code>
3. Отдельная тема разговора: долгая и нудная.

Answer 5

It is best to make a separate subdomain. For example: m.domen.ru, mobile.domen.ru, wap.domen.ru
I define it like this:

$ua = str_replace('windows ce', '', strtolower($_SERVER['HTTP_USER_AGENT']));
if (!(strpos($ua, 'windows') !== false || strpos($ua, 'linux') !== false || strpos($ua, 'bsd') !== false || strpos($ua, 'x11') !== false || strpos($ua, 'unix') !== false || strpos($ua, 'macintosh') !== false || strpos($ua, 'macos') !== false))
{
  header("Location: http://m.domen.ru");
}

This is not very correct, since only NOT computers are redirected, but what is NOT a computer is a mobile device.
Javascript is not recommended - not all phones understand (old)

Answer 6

A small offtopic from the point of view of the user of these same mobile sites (iPhone as a phone)
Example 1. Wikipedia.
When entering the site, a redirect is made to the mobile version, which is very convenient (formatting for the screen of my device, sections open on clicks, which is convenient, since there is no sheet that scrolls for a long time and is not convenient). But there are also disadvantages.
The redirect occurs at the moment when the full page is fully loaded (not for mobile devices). And then the download of the mobile version begins. This, of course, happens only on the 1st visit to the page (not just 1 time, but on the first visit), but it’s insanely annoying, because not only is the traffic wasted, but it also takes much longer to wait (especially when taking into account the speed of mobile Internet). For me, the waiting time is more critical, since information is often needed urgently.
In addition, zoom cannot be used in the mobile version. Sometimes you need to see the picture better and it doesn’t work, you have to load it in a separate tab completely.
Example 2. An online store, the name of which I will not name.
In principle, everything is quite convenient and there is access to all information. But again, disadvantages.
1) There are no filters and options to choose from. Well, I don’t want to flip through 10 pages in an attempt to find what I need, if, for example, I know for sure that there will be only a few models to choose from and the list can be easily reduced using a couple of filters.
2) Having found no filters and deciding to switch to a full-fledged site, so as not to suffer, what will an ordinary user do? Click on the link "Go to the full version of the site" somewhere at the bottom of the page. Here, following this link leads to the main page of the desktop version. Always. To the same place. And again I have to go through 3-4 pages just to get to the section where I was already and finally start using filters. And this is on a mobile phone, which the site takes longer to load and render too. Incredibly annoying.
Moreover, this behavior is not only for this particular store, at least a couple of large online stores and even the most popular of Ukraine's online catalogs suffer from the same attitude towards the user.
All this means that if there is a mobile version, try not only to redirect to it, but also to optimize it for mobile users. Don't make us suffer.
Here the redirect occurs immediately, which pleases.