SMB3-RS
SMB3-RS is a browser-based randomizer for Super Mario Bros.
What SMB3-RS is
SMB3-RS is a browser-based randomizer for Super Mario Bros. 3. It rebuilds each world map instead of only changing level order, and can randomize power-ups, enemies, chest items, and palettes. Players supply their own Super Mario Bros. 3 (USA Rev 1) ROM; the ROM remains on the user’s machine while processing runs in the browser. The tool outputs an IPS patch or a patched ROM. Sharing a seed and flag key lets others generate the same game, while pasting a flag key reproduces another player’s settings for races or cooperative play. The browser version runs on Windows, macOS, Linux, and mobile without installation. The repository also includes a native command-line tool for batch testing and debugging, and lists an MIT license.
Good
- Rebuilds complete world maps
- Randomizes multiple game elements
- Keeps the ROM on your machine
- Supports shared seeds and flag keys
- Runs without installation
Watch out
- Requires a Super Mario Bros. 3 ROM
- Browser page gives no price details
- Focused on one specific game
Who it suits
SMB3-RS suits players who want customizable Super Mario Bros. 3 randomization and reproducible races. It also fits users comfortable supplying their own ROM and using browser-based tools.
Verdict
SMB3-RS offers broad, reproducible randomization through a browser, with patches suitable for solo play or shared races. Its ROM requirement and game-specific scope are the main practical considerations.
The facts
Each one read from SMB3-RS's own pages, with the date it was checked.
Where it runs
- Browser-based
- The randomizer runs entirely in a browser.checked 9 Oct 2026
- Platform access
- The browser-based tool runs on Windows, macOS, Linux, or mobile without installation.checked 9 Oct 2026
What it does
- Bug reports
- The project asks users to file bugs as GitHub issues and include the run's seed and flag key.checked 9 Oct 2026
- Command-line tool
- The repository also provides a native CLI used for batch testing and debugging.checked 9 Oct 2026
- License
- The repository lists an MIT license.checked 9 Oct 2026
- Local processing
- Randomization runs locally via WebAssembly, and the ROM stays on the user's machine.checked 9 Oct 2026
- Output formats
- The tool generates an IPS patch or a patched ROM.checked 9 Oct 2026
- Pricing
- The opened page does not state a price or whether the tool has a free plan.checked 9 Oct 2026
- Purpose
- SMB3-RS is a browser-based randomizer for Super Mario Bros. 3.checked 9 Oct 2026
- Randomized elements
- It can randomize power-ups, enemies, chest items, and palettes.checked 9 Oct 2026
- Reproducibility
- Users can paste a flag key to reproduce another person's settings.checked 9 Oct 2026
- ROM requirement
- Users provide their own Super Mario Bros. 3 (USA Rev 1) ROM.checked 9 Oct 2026
- Seed sharing
- Sharing a seed and flag key gives players the identical game.checked 9 Oct 2026
- Use with friends
- The shared seed and flag key support races or playing alongside friends.checked 9 Oct 2026
- World maps
- It rebuilds each world map rather than only shuffling levels.checked 9 Oct 2026
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