Zuul is an open-source continuous integration system with project gating. It tests proposed changes together with the changes they depend on and merges them only when the tests pass, which keeps the main branch in a working state. Zuul supports cross-project dependencies and lets teams define jobs as Ansible playbooks. It is aimed at organisations with many repositories and large development communities. Zuul is software that the operator installs and runs on its own infrastructure, so it can serve as a self-hosted alternative to hosted CI services.
Zuul is licensed under the Apache 2.0 licence and is developed under the OpenInfra Foundation, which describes itself as part of the Linux Foundation, a non-profit in the United States. Because Zuul is self-hosted, the data it processes stays where the organisation deploys it, and no vendor-operated cloud service is involved. European organisations still need to check the external systems their pipelines connect to, such as source-code hosts and package registries.