Bin design file format

A bin design file is a JSON text file that holds one design from the bin designer of the Gridfinity Layout Tool. It stores every setting of the bin, so you can open it again later and carry on with the design. It is not a printable model. To print, export an STL, 3MF or STEP file.

Use a design file to back up a design, send it to a friend, or move it to a different browser. The published schema is at gridfinitylayouttool.com/schema.

Export a design file

Export a design file from the export dialog of the bin designer, or from the menu of a design in Saved designs. Save and reuse designs gives the steps.

The file takes the name of the design. If the design has an imported STL shape, the file holds a copy of it. You don't need to send any other files.

INFO

A Workshop build has no design file. The Download JSON item shows only for bin designs.

The file always holds a standard base. If the design uses a low-profile base, the export removes it, and the layout that you import the design into sets the base profile again.

Import a design file

In Saved designs, click Import. Then drop the file, or paste the JSON text into the Design JSON box. Read the summary under Ready to import design before you import. Save and reuse designs gives the full steps.

The design goes into your saved designs and opens in the bin designer. The drop area also takes the STL file of a whole Gridfinity bin, which becomes a saved design with a fixed shape.

What the file holds

The file wraps the bin settings in a small envelope:

Field	Required	What it holds
$schema	No	The schema address, for your code editor. The importer ignores it.
type	Yes	Always "gridfinity-bin-design". The importer rejects other values.
version	Yes	Always "1.0"
name	Yes	The design name
params	Yes	All bin settings
_meta	No	Where and when the file was exported

The params object has nine required fields. You can leave out every other setting, and the importer fills it with its default value.

Field	Unit	Range	What it sets
width	Grid units	0.5 to 16, in steps of 0.5	Bin width
depth	Grid units	0.5 to 16, in steps of 0.5	Bin depth
height	Height units	1 to 50. Only a spacer can be 1, other bins need 2.	Bin height
gridUnitMm	mm	20 to 60	Size of one grid unit. Standard Gridfinity is 42.
heightUnitMm	mm	3 to 20	Size of one height unit. Standard Gridfinity is 7.
wallThickness	mm	0.4 to 2.4	Outer wall thickness
base			The base, with a style such as "standard" or "magnet"
style		"standard", "slotted" or "solid"	An open bin, a bin with divider slots, or a solid block for cutouts
compartments		1 to 12 columns and 1 to 12 rows	The compartment grid

The compartments object has cols, rows, a divider thickness in mm, and a cells list. The cells list gives one compartment number for each grid cell, row by row. Cells with the same number make one large compartment.

Avoid the traps

• Heights are height units. "height": 3 is a 21 mm bin at the standard 7 mm height unit.
• Some widths are percentages. The width of a label tab, a handle and the wall cutouts is a percentage of its span. The label tab depth is in millimeters.
• The cell count must match. The cells list needs exactly cols multiplied by rows entries.
• Leave out two fields. The app adds the magnet position from the layout and the nozzle size from your print settings. Do not write them in a file.

A minimal design

This file holds a 2 by 2 bin, 3 height units tall, with one compartment and a stacking lip:

{
  "$schema": "https://gridfinitylayouttool.com/schema/bin-design.schema.json",
  "type": "gridfinity-bin-design",
  "version": "1.0",
  "name": "Minimal bin",
  "params": {
    "width": 2,
    "depth": 2,
    "height": 3,
    "gridUnitMm": 42,
    "heightUnitMm": 7,
    "wallThickness": 1.2,
    "style": "standard",
    "base": { "style": "standard", "stackingLip": true },
    "compartments": { "cols": 1, "rows": 1, "thickness": 1.2, "cells": [0] }
  }
}

Validate a file

Keep the $schema line at the top of the file. Most code editors then mark a wrong field or value while you type.

The importer applies more rules than the schema. It rejects a file when:

• type is not "gridfinity-bin-design", or the file has no version or no name
• the width, the depth, the height or a unit size is not a number above zero
• style is not one of the three styles
• cols or rows is not a whole number from 1 to 12

The importer lists each problem that it finds. Until you correct them, the import button stays off, so a file with problems never reaches your saved designs.

Next steps

• Layout file format: a layout file can carry its designs inside it.
• Save and reuse designs: the saved designs list, versions and variants.
• Saved designs and linked bins: how a layout uses a saved design.
• File formats: STL, 3MF and STEP for printing.