SMB3 Foundry
SMB3 Foundry: A free, open-source desktop editor for shaping and testing Super Mario Bros. 3 levels. Ranked #23 of 49 in ROM Hacking Tools by our editors (5.2/10); pricing: Free plan; best for editing and testing levels for one game.
At a glance
- Editor score5.2 / 10
- PricingFree plan
- Best forEditing and testing levels for one game
- Free planYes
- Paid fromNone
- ROM editingYes
- Facts checked5 Oct 2026
Where it wins
- Move, copy, cut, paste, and remove multiple level objects
- Undo and redo edits, then test levels without overwriting the ROM
- Downloads are available for Windows, macOS, and Linux
Where it doesn't
- Supports the US release of Super Mario Bros. 3 only
- Focused on level editing rather than full game editing
- Community is the listed support channel
Our verdict on SMB3 Foundry
SMB3 Foundry is a desktop editor for Super Mario Bros. 3 ROM files, aimed at people creating ROM hacks based on the game. It lets users select and view levels, inspect blocks and objects, and load or save levels in ROM files. The focus is practical level work: users can edit vertical levels, change palettes, music, and level jumps, and create level screenshots. It is free and open source, with downloads for Windows, macOS, and Linux. For a project centered on changing and checking SMB3 levels, its focused toolset is the main appeal; it is not positioned as a full game editor.
Editing controls cover selecting, moving, removing, copying, cutting, and pasting multiple objects, with undo and redo for revisions. A notable workflow detail is that levels can be tested directly without overwriting the ROM, which can help keep testing separate from saved ROM changes. The project also includes SMB3 Scribe, a separate overworld editor, so overworld work is not part of Foundry itself. Manuals are provided, and the listed support channel is community. This is a better fit for solo users who want a desktop workflow for level design than for anyone seeking a broad, multi-game ROM editing suite.
Version compatibility is an important boundary: the vendor identifies the US release of Super Mario Bros. 3 as supported and says support for other versions is not planned right now. That makes the choice relatively clear for a hack based on that release, but a poor match for work targeting another version or game. The free plan and cross-platform desktop downloads keep access straightforward, while the narrow game-specific scope means buyers should choose a broader editor if they need tools beyond SMB3 level editing. For focused level creation, testing, and object changes, Foundry covers the core tasks without claiming to replace a complete game editor.
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SMB3 Foundry pricing
SMB3 Foundry fact sheet
| Free plan | Yes |
|---|---|
| Paid from | None |
| ROM editing | Yes |
| Patch formats | Not verified |
| Tile/sprite editing | Not verified |
| Hex editor | Not verified |
| Supported platforms | Linux, Windows, macOS |
| Game scope | Specific game |
| Deployment | Desktop |
| Platforms | Windows, macOS, Linux |
| Support | Community |
| Built for | Solo (editorial estimate) |
| Pricing | Free plan |
| Website | github.com |
| Facts checked | 5 Oct 2026 |
Alternatives to SMB3 Foundry
- YY-CHRA focused Windows dot editor for viewing and editing graphics in retro-game ROMs.8.4
- NUPSA free Windows desktop utility focused on creating and applying UPS patches.7.3
- HxDA broad Windows hex editor for binary work, rather than a ROM-specific hacking suite.7.2
See all SMB3 Foundry alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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