Can I use C# scripting and Javascript in the same project?

Hello sir, follow this link Unity talking to Arduino via WiFi/Ethernet - Questions & Answers - Unity Discussions “Unity talking to Arduino via WiFi/Ethernet” that you shared your answer, I have tried to use your code in unity but the problem is javascript cannot find C# class and error. How can I solve this problem?87188-16443527-10211903693018634-930548116-n.jpg

Move the c# files into the /Standard Assets folder to make that be compiled at an earlier stage and thus accessible to your js scripts. Unity - Manual: Special folders and script compilation order

Yes you can, but i would highly recommend to chose one of the two and stick with it the rest of the project. In my experience it tend to get funky when i have scripts in different languages. Unity is optimized for C# and JS doesn’t want to access my C# scripts so i would recommend C#.