Build Sandbox
by Wilkcraft
Build Sandbox is a NeoForge mod for 1.21.1 that adds an isolated creative building dimension, where players design structures without touching their survival world.
What it does
A player uses a command to enter a separate flat creative world built for testing builds. On first execution the mod saves the player's survival position, dimension and inventory, then teleports the player into the sandbox dimension and switches to Creative mode with a sandbox inventory. Running the command again returns the player to the saved survival state.
Because the sandbox is kept apart from survival, experiments and test structures stay out of the main world. The mod tracks its data per player, so switching between the two worlds keeps each player's state intact and persistent across sessions. Build Sandbox runs on client and server, so the server and every player need the mod, and it is published for NeoForge 1.21.1 only.
Key features
Isolated sandbox dimension
A flat creative world exists apart from survival, so builds can be tested without changing the survival world.
Command-based entry
A command moves the player into the sandbox and back out, with no extra setup needed in the world.
Saved survival state
Position, dimension and inventory from survival are stored when the player enters and restored on return.
Per-player data
Each player's sandbox and survival data is kept separately, and switching between worlds keeps it persistent.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Testing builds
Players design and check structures in a clean, controlled space before placing them in their survival world.
Keeping survival untouched
Experiments stay in the sandbox, so survival blocks, items and position are not altered by the trial builds.
Who it’s for: Players who build large structures and want a dedicated creative space, and server owners who need a sandbox that keeps individual players' survival progress separate.
How it compares
Selective Creative Inventory is a NeoForge 1.21.1 mod for client and server under the MIT License and is open source, so it changes creative inventory access rather than providing a separate building world. Schematicon is also NeoForge 1.21.1, client and server, MIT License and open source, and it deals with schematics. Simply Fly is server-side only, not open source, and is licensed as All rights reserved on NeoForge 1.21.1, so players join without installing anything.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Build Sandbox | NeoForge | 1.21.1 | Client and server | 2026-09-26 |
| Selective Creative Inventory | NeoForge | 1.21.1 | Client and server | 2026-07-18 |
| Schematicon | NeoForge | 1.21.1 | Client and server | 2026-07-19 |
| Simply Fly | NeoForge | 1.21.1 | Server-side only | 2026-03-04 |
Questions
Does Build Sandbox need to be installed on the server?
Is the survival world affected while the sandbox is in use?
Which versions does Build Sandbox support?
In the catalog
Build Sandbox is one of 29,952 Game mechanics mods on ModsFinder, and one of 12,140 Game mechanics mods for NeoForge. 32,366 mods support Minecraft 1.21.1.
More from Wilkcraft
Similar mods
What the author says
Build Sandbox is a NeoForge mod for Minecraft 1.21.1 that adds a fully isolated creative building dimension where players can design structures safely without affecting their survival world. This ensures that switching between worlds is seamless and persistent.
Official listing
- Modrinth page
- modrinth.com/mod/build-sandbox
- Owner
- Wilkcraft
- Published
- 2026-06-17
- Updated on Modrinth
- 2026-09-26
- Facts verified
- 2026-10-15