Hi there! I’ve been working with development for FiveM for a while now, for a large well known role play community which I can provide proof of if necessary. I have also worked with several smaller role play servers to create custom scripts or install already available ones. An inventory system should not be too hard, however I may need further information from you, for instance is this to create a custom inventory script or install a ready made one and tweak it? Do you already have a database setup? Are you using ESX?
If necessary, I will most likely develop this script in C# and NUI and share with you the source code.
Looking forward to working with you!