IMO, it's much the same and pretty much only a question of API. Property-based testing (like QuickCheck) generates randomness using a PRNG, creates a structure

IMO, it's much the same and pretty much only a question of API. Property-based testing (like QuickCheck) generates randomness using a PRNG, creates a structure from that, and checks that some property holds for that structure. A fuzzer generates some arbitrary input and usually checks that the program returns successfully (i.e. doesn't crash). The reason I think they are the same is that we can rather easily turn one into the other and vice versa: - A PBT test can be turned into a fuzzer-test by sourcing the randomness from the input instead of a PRNG and failing the program if the property does not hold. - A fuzz-test can be turned into a PBT by sourcing the input from a PRNG. The real difference is that fuzzers tend to be coverage-guided, i.e. a fuzzer will use what part of your code is executed to guide its mutations and thus steer it towards more "interesting" inputs.