The official Steam page lists Workshop support and describes Sandustry as a game built with modding in mind. At the same time, many players use the word "mods" to mean shared layouts, blueprint ideas, or custom challenge setups, and each category leads to different tools.
Workshop content, shared layouts, and rule-bending shortcuts are three different things that all get called "mods." Separate them and each path is easier to follow.
This is the classic meaning: player-made additions or rule changes distributed through a platform such as Steam Workshop. The clearest early example is SandTogether, the community co-op mod.
Many players really want a good layout to copy or study. That is useful, but it is not the same thing as a code-level mod.
Cheats, trainers, and save edits change how the game behaves rather than adding content, so they need a different page from Workshop mods.
If you are really trying to skip the grind or test layouts quickly, head to the cheats page rather than looking for a Workshop mod.
Workshop activity is real, and the branch status moved forward in v0.5.6. Modding still lives on a separate track from normal live-branch vanilla play, but the branch is no longer stuck behind 0.5.5 in the current official notes.
Update #3 says the mods branch is now on 0.5.6 and adds several new hooks and helper
methods, including building:removing, fire:terrain:burn, and
meltAtCell.
That does not make the mods branch identical to normal vanilla play, but it does make the
older "behind live build" wording too stale as a current summary.
Use the current patch notes for the latest release-state read, then use the Aug 29 developer post for the broader roadmap context.