MySQL
Software that is both open source and proprietary typically falls under dual licensing models. Examples include
MySQL, which offers an open-source community edition alongside a proprietary version with additional features, and MongoDB, which provides an open-source version with a commercial license for its advanced offerings. Another example is the Qt framework, which is available under both open-source and commercial licenses, allowing developers to choose based on their project needs. This model allows companies to leverage the benefits of open source while also monetizing their software through proprietary licenses.
