Coming from an Apache background, the first thing to understand is that Nginx doesn't process .htaccess files at all. While Apache searches for and reads .htaccess files in every directory for each request, Nginx relies entirely on its main configuration file for performance reasons. This architectural difference means:

# Apache .htaccess example
RewriteEngine On
RewriteRule ^old-page\.html$ new-page.html [L,R=301]

# Equivalent Nginx server block
server {
    rewrite ^/old-page\.html$ /new-page.html permanent;
}

The syntax variations between Apache's mod_rewrite and Nginx's rewrite module are significant:

• Apache uses RewriteRule directives while Nginx uses rewrite directives
• Nginx doesn't have [L] flag - it processes directives in order
• The permanent (301) and redirect (302) flags come after the pattern
• Nginx uses ~ for regex matching (similar to Apache's [NC])

Here's how common Apache rewrites translate to Nginx:

# Apache: Remove www
RewriteCond %{HTTP_HOST} ^www\.example\.com [NC]
RewriteRule ^(.*)$ http://example.com/$1 [L,R=301]

# Nginx equivalent
server {
    server_name www.example.com;
    return 301 $scheme://example.com$request_uri;
}

For more advanced cases like front controllers:

# Apache typical front controller pattern
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

# Nginx equivalent
location / {
    try_files $uri $uri/ /index.php?$query_string;
}

The Nginx approach offers several advantages:

• Single configuration load vs per-directory .htaccess parsing
• Faster regex processing in the core engine
• Simplified debugging with centralized configuration
• Better handling of high traffic loads

Watch out for these frequent issues:

1. Forgetting that Nginx matches the most specific location block first
2. Not properly escaping special characters in regex patterns
3. Missing the $request_uri variable when doing redirects
4. Assuming if/else logic works the same way as Apache's RewriteCond

When transitioning from Apache to Nginx, one of the first hurdles developers face is the absence of .htaccess files in Nginx. Unlike Apache which processes .htaccess files recursively in each directory, Nginx requires all rewrite rules to be defined in the main server configuration file (typically nginx.conf or included files) for performance reasons.

Let's examine some common Apache rewrite patterns and their Nginx equivalents:

# Apache .htaccess
RewriteEngine On
RewriteRule ^old-page\.html$ /new-page.html [R=301,L]

# Nginx equivalent
server {
    location = /old-page.html {
        return 301 /new-page.html;
    }
}

The fundamental differences in rewrite implementation:

• Nginx uses return for simple redirects instead of RewriteRule
• Nginx's rewrite directive has different flags (break, last, redirect, permanent)
• Apache's [L] flag becomes last in Nginx
• Conditional logic uses if blocks differently in Nginx

For more advanced use cases, here's how to handle complex rewrites:

# Apache
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

# Nginx equivalent
server {
    location / {
        try_files $uri $uri/ /index.php?$args;
    }
    
    location ~ \.php$ {
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_pass unix:/run/php/php8.1-fpm.sock;
    }
}

Nginx's approach offers significant advantages:

• No directory scanning for .htaccess files
• Rules are compiled once at server start
• Better handling of concurrent requests

When converting existing rules:

• Use tools like htaccess-to-nginx-converter
• Test thoroughly with nginx -t before reloading
• Consider using map directives for complex rewrite scenarios