namakemon

A standard JSON implementation to rule them all:
https://github.com/ndee85/coa_tools/issues/26
There's actually software like Affinity Designer that supports exporting to Spine JSON 

Please make Spriter receive JSON so Spriter can receive sprites directly from graphic applications and then you (Brashmonkey) talk to Affinity so they add an option inside Affinity Designer so Spriter can be part of the workflow too.
Please also add first party (developed and supported by you instead of third parties) runtimes (instead of first party converters) for Unity and most used.
If possible add real time editing directly from Spriter into Unity like Toon Boom does.
 

Mike thanks for reply!
SpriterGM creating Game Maker child objects from spriterModel_instance and manipulate with objects parameters (x,y,image_angle and etc). In feature we are planing to add deataching functions (for example: to behead the enemy), errors handling functions, supporting spriter metadata and spriter objects like point or box
Now SpriterGM supports:
playing animation from scml
blending animations
character maps
trigger events
sound events

For example:
SpriterGM_features_demo.gmz
 

Spriter 2D: Game Maker Studio extension package
SpriterGM is DLL based extension package for Game Maker studio
Requirements: GameMaker studio 1.4+.
1.1.0 update:
added manual bone control added two bone IK minor bug fixes Installation:
1. Create new game maker project.
2. Download SpriterGM extension from Github SpriterGM.gmez or YoYo Marketplace
3. Drag and drop SpriterGM.gmez file on Extensions folder in resurces window of your game maker studio project.
4. Select SpriterGM package in Extensions folder and open propierties window (Alt+Enter)
5. Select Import Resources tab and press Import all button.
Example projects:
Example 1: Loading spriter instance
Example 2: Animations blending
Example3: Spriter event trigger uses
Project source code: SpriterGM Github
SpriterGM guide: Spriter 2D integration for Game Maker 1.4+
Tutorial video: