@danluu @shajra fuzzers are more blackbox oriented/autonomous, PBT is greybox and you need to come up with the properties to check (via autogenerated inputs). Coming up with props is somewhat hard, but then serve as a specification of your impl. Main diff sounds like, a fuzzer can discover a crash, not a non-crashing but logically incorrect answer. I can imagine a small intersection in usecase, like your describe the data corruption test. See the Quickchecking Dropbox paper.