ZYpp (or libzypp; "Zen / YaST Packages Patches Patterns Products"[6]) is a package manager engine that powers Linux applications like YaST, Zypper and the implementation of PackageKit for openSUSE and SUSE Linux Enterprise.

On June 2, 2009, Ark Linux announced that it has completed its review of dependency solvers and has chosen ZYpp and its tools to replace the aging APT-RPM,[9] as the first distribution to do so.

Using it for the full installing process brought it to its limits, and adding extensions such as support for weak dependencies and patches made it fragile and unpredictable.

[11] Projects like Optimal Package Install/Uninstall Manager (OPIUM)[12][13] and MANCOOSI[14] were trying to fix dependency solving issues with a SAT solver.

[15] The SAT solver implementation as it appears in openSUSE 11.0 is based on two major, but independent, blocks: After several months of work, the benchmark results of this fourth ZYpp version integrated with the SAT solver were more than encouraging, moving YaST and Zypper ahead of other RPM-based package managers in speed and size.