Read How it work here:
https://mcengine.github.io/mcbackpack-website

Central Server API Support Repository: https://github.com/MCEngine/server-expressjs

Note: ngrok is currently used for testing purposes.
Please replace the ngrok configuration with your own domain.
Update API_TOKEN too.

Need Core

Platform SpigotMC PaperMC FoliaMC
Compatibility: This has only been tested with 26.1
Requirement: Requires Java 25+.

resource pack
You can clone repo and zip it yourself.