The Jake Group

The purpose of this plugin is to facilitate deployment of subdomain links to 
landing pages on a WordPress website. The plugin automatically maps subdomains 
to page and post permalinks based on the post_name field in the database. 
There are no administrative settings.
This plugin DOES NOT edit DNS zone files. Subdomain DNS records themselves 
either need to be set up individually or as a wildcard record in the DNS zone 
file to map to the website directory. Once the request reaches the WordPress 
system, the plugin will automatically check to see if the subdomain matches a 
page or post name. If so, the WordPress query is edited to get that page/post 
at its permalink. The WordPress siteurl is excluded, as is the naked 
second-level domain.
Example mappings:
URL → Mapping 
http://example.com → default homepage (no remapping) 
http://www.example.com → default homepage (no remapping) 
http://test-page.example.com → example.com/test-page/ 
http://mypost.example.com → example.com/mypost/

Automatic Subdomains

Automatically maps subdomains to page and post permalinks based on post slug.

Jam Viet

If you do not like WordPress Multisite and do not want to separate Your database, WP Super Subdomains will help you, this plugin work like charm without complicate setting, just active it and enjoy !
All your tag, Category, page or author will turn to subdomains and it depend on your setting !
Works perfectly with cache plugin like W3C Total Cache or WP Super Cache ! And thanks to Erick Tampubolon ( http://www.lontongcorp.com ) for create <code>WP subdomains revisited</code> ! i have some idea from that plugin but my plugin run faster and better than his one !
<h4>Features</h4>
<ul>
<li>Setup main categories as subdomains</li>
<li>Setup tag as subdomains</li>
<li>Setup main pages as subdomains</li>
<li>Setup author archive as subdomains</li>
<li>Auto redirect to new links using 301 redirect ! Do not harm your Backlink or Visitor !</li>
</ul>
If you want to create login page like this: <code>login.domain.com</code> please do something in wp-config.php file !
Please go to <a href="http://www.jamviet.com/2016/03/plugin-wp-super-subdomains-create-subdomains-second.html" rel="nofollow ugc">My English Post</a> to read more, or if you have a new idea please tell me there !
<h3>Instructions</h3>
Remember to read instruction in Setting Page

WP Super Subdomains

This plugin allow you create subdomain without using Wordpress Multisite ! Setup your main categories, tag, pages, and authors as subdomains !

Automatic Subdomains vs WP Super Subdomains