To install JEM4 you minimally need:

- A working Joomla4 installation
- PHP 8.0 or higher
- MySQL database

The JEM installer will check for minimal version requirements and will abort the install if they are not met.  


The following PHP settings are recommendend:

max_execution_time >= 30
memory_limit >= 32M  (>= 64M recommended) - depends on other Joomla extensions used
safe_mode >= off
allow_url_fopen >= on
upload_max_filesize >= 4M

For local development you can use a local webserver of your choice e.g. Apache or IS.