If you’re looking to modularize your HTML code by including shared headers, footers, or snippets, Server-Side Includes (SSI) is a simple and effective solution. This guide walks you through enabling SSI for .html, .htm, and .shtml files using Apache 2 and .htaccess.

Step 1: Enabling mod_include on Apache

Make use mod_include must be enabled and is running. This module is generally available with the default Apache 2 setup. To enable it on Debian, execute the following command:

sudo a2enmod include
sudo systemctl restart apache2

Step 2: Set XBitHack flag

. XBitHack allows to parse files for server side includes as long as they have the execution bit set. Make below configuration in .htaccess file:

XBitHack On

Step 3: Configure File type for SSI

Add file types to be enabled for server side include (SSI) in.htaccess configuration like below:

AddType text/html .html .htm .shtml
AddHandler server-parsed .html .htm .shtml

Add ‘Includes‘ to the Options directive in.htaccess:

Options -Indexes FollowSymLinks Includes

So, the overall SSI configuration for various html file types would be:

XBitHack On
AddType text/html .htm
AddType text/html .shtml
AddHandler server-parsed .html
AddHandler server-parsed .htm
AddHandler server-parsed .shtml
Options -Indexes FollowSymLinks Includes

Step 4: Restart Apache

Finally restart Apache to make the changes reflected.

sudo systemctl restart apache2

Reference: MOD_INCLUDE

Conclusion

SSI is still a valid and lightweight method for HTML content modularization on Apache servers, especially for static or CMS-based sites. Ensure you configure it securely and use it in performance-aware environments.