The Unending Galaxy Game Editor is a key component in modifying the game. Using the Game Editor, you can create or modify various agents (ships, asteroids, factories, and stations), items (wares, weapons, and shields), maps, and other game settings (tech groups, game profiles, factions, and animations). These modifications can optionally be shared on the Unending Galaxy Steam Workshop.

A mod can easily be generated using the game editor's built-in mod creation tool. Simply open the editor, go to File → Create new mod…, and follow the instructions.

Uploading is handled by the Unending Galaxy Workshop tool (Neo SPQR). To upload a mod, follow the instructions here.