I am not a lawyer. IIUC GPL is fine unless you want to make something that 'links to' the GPL licensed code, then the code you made has to be GPL as well. The

I am not a lawyer. IIUC GPL is fine unless you want to make something that 'links to' the GPL licensed code, then the code you made has to be GPL as well. The way I understand that is if, in your python app, you 'import gpl_licensed_lib' ... then you are boud by GPL to redistribute your source under GPL. That would be OK, if you were permitted to sell GPL based software without giving away the source under GPL, which you are not. TLDR: GPL is infectious, which is great for protecting GNU software like Linux, but it also makes it complicated for people to build and sell commercial software on Linux. I build Django apps for clients, and I avoid any python library that's GPL only.