Pickling is just one specific type of marshalling, so the terms are not equivalent. I'm not familiar with Ruby, but from your link it's clear that the Marshal l

Pickling is just one specific type of marshalling, so the terms are not equivalent. I'm not familiar with Ruby, but from your link it's clear that the Marshal library is also for one specific marshaling format. By the way, pickling is great for transmitting data at runtime between processes that you own, because it can marshal almost any Python object and it's very fast. But it's bad at storing data (on disk or in a database) because it can execute arbitrary code and the format of the objects can change between package releases. That's quite different from marshaling as JSON, which is a very stable format supporting a deliberately restricted set of types.