What is the crowd's opinion of HTerm?

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hterm comes to mind.

I have yet to find another serial monitor that comes close in features. Just to read log messages/log into a serial console, screen or pyterm are much more convenient, but if you want to debug a serial data stream, the features of this old freeware tool are godsend!

Although it's positively ancient, I still haven't found anything better at this than hterm.

To snoop on a live connection while it's active, a logic analyzer is your goto tool.