This article covers How to Fix 404 Page Not Found Error in Codeigniter and run Codeigniter  application from subdirectory on Nginx.

For example, we may have an application running at example.org but need a second application running at example.org/blog.

This feels like it should be simple, but it turns out to be more complex and fraught with confusing Nginx configurations!

Here’s the working configuration to have two Codeigniter apps working, where one application exists in a subdirectory of another.

server { listen 80 default_server; listen [::]:80 default_server; root /var/www/top/public; ...