If you already have animations or want to integrate Spine into a project, the Spine Runtimes are free and open-source on GitHub.
Because Spine 3.8.99 is a frequent "frozen" version for many long-term projects, the community provides free assets for it: spine 3899 free
These runtimes allow your game engine (Unity, Godot, Cocos2d-x) to load and play .json or .skel files exported from Spine 3.8.99. If you already have animations or want to
Users can often select specific legacy versions within the launcher to test compatibility with older game engines like Godot 3.x. and inverse kinematics (IK) tools.
Use the full suite of rigging, meshing, and inverse kinematics (IK) tools.