: A free version for non-commercial use.

: Supports Class, Sequence, State, and ER diagrams.

One of its strongest suits is its "hackable" nature. It uses a JavaScript-based extension API, allowing users to build their own plugins or integrate with external tools.

: While not a dedicated "modeling" engine with code generation, it is the best free tool for quickly drawing UML-compliant diagrams. Start Drawing 3. Why Avoid "Free Keys" Online? Security Risk : Sites claiming to have "hot keys" are primary sources of ransomware Unstable Software