M-Box is a browser-based generator for designing custom 3D-printable storage boxes. Import STL or 3MF models to create contour-following cavities, or combine eight basic shapes while tuning box dimensions, wall thickness, corner radius, cavity clearance, and smoothing with a real-time 3D preview.

All geometry processing runs locally in the browser for privacy. Designs can be saved as reusable templates and exported as standard 3MF files ready for slicers and 3D printing.