StarUML is a free, open-source modeling tool that supports UML 2.4. It offers a wide range of features, including:
Old hacks involved editing your hosts file to redirect license.staruml.io to 127.0.0.1 . Modern StarUML versions compile a signature check into the binary. If the validation server is unreachable, the software eventually disables saving after 14 days. License Key Staruml
. This is the only way to receive a valid key that removes watermarks from exported diagrams and allows for continued use beyond the 30-day evaluation period. StarUML License Overview Perpetual License StarUML is a free, open-source modeling tool that
A is a unique alphanumeric code provided by MKLabs that unlocks the full professional features of the software. While StarUML was originally an open-source project (Version 1), modern versions (starting from Version 2) are commercial software that require a paid license for continued use. StarUML Licensing Model If the validation server is unreachable, the software
StarUML uses a , where a license key is required to remove watermarks and access full "Pro" features. As of July 2025 , the licensing model shifted from user-based (tied to a person) to device-based (tied to the installation machine) to reduce legal ambiguity and simplify management for administrators. Licensing Model & Cost
There are a few ways to obtain a license key for StarUML:
A license is tied to a specific installation on a single machine. Easy Transfer: