The conceptual difference is the file format, as with klog the main idea is to have a format that looks and feels “natural”. So when opening a `.klg` file you don’t need to know much about the format in order to make sense of it, yet the data can be parsed and processed. And you can type in the entries by hand in a text editor, due to the simple and memorable syntax.

The data format in timewarrior is more opaque, even though it’s still plain text of course. There are, by the way, also cool projects that use sqlite as underlying datastore, like https://github.com/samg/timetrap , which produces a similar output as timewarrior.

I guess both philosophies have different strengths and weaknesses, depending on what is important to you.