Not at all a fan of apps that run a webserver locally and interface through a browser. Will make a rare exception, but I wouldn't use one long term. Not exact

Not at all a fan of apps that run a webserver locally and interface through a browser. Will make a rare exception, but I wouldn't use one long term. Not exactly what you are asking, but similar. I do like the mature pattern of having a number of CLI programs that can be run, and an additional GUI that can run them as well, for non-expert or infrequent users. Have a log that shows what commands are called by the GUI. This gives powerful automation potential for free. Look at Handbrake GUI wrappers for technical inspiration, if not UX design. Then you can do whatever IPC you like, can be as simple as reading from stdin/out or maybe Unix sockets before resorting to TCP/IP. If work has to be done outside of the user session, write a service/systemd module definition with one of the CLIs. Re: Data, as others mentioned sqlite can stretch a lot farther than was commonly believed until a short while ago. Try before resorting to servers.