Machine configuration

When you add components through the Viam app, you’re building a JSON configuration that tells viam-server what hardware is attached and how to talk to it. Understanding this configuration structure helps you work faster. You can edit JSON directly, copy configurations between machines, and debug issues by reading the raw config.

Configuration blocks

Every component in your machine’s configuration is a JSON block with these fields:

FieldWhat it does
nameA unique name for this component on this machine. Your code references the component by this name.
apiThe component type, in the form rdk:component:<type> (for example, rdk:component:arm).
modelThe specific driver, in the form namespace:family:name (for example, viam:ufactory:xArm6).
attributesModel-specific settings that control how to connect to the hardware and how it should behave.
depends_onOther components this one requires (for example, a motor depends on a board).
frameOptional spatial relationship to a parent component, used by the motion service.

Example: a motor controlled by a board

Here’s a simple configuration with a Raspberry Pi board and a DC motor connected to its GPIO pins:

{
  "components": [
    {
      "name": "my-board",
      "api": "rdk:component:board",
      "model": "pi",
      "attributes": {}
    },
    {
      "name": "my-motor",
      "api": "rdk:component:motor",
      "model": "gpio",
      "attributes": {
        "pins": {
          "a": "13",
          "b": "15",
          "pwm": "12"
        },
        "board": "my-board"
      },
      "depends_on": ["my-board"]
    }
  ]
}

A few things to note:

  • The board uses pi, a built-in model. No attributes are needed because the Pi’s GPIO layout is known.
  • The motor uses gpio, a built-in model for DC motors driven by GPIO pins. The pins attribute maps the motor’s control wires to specific board pins.
  • depends_on tells viam-server to initialize the board before the motor, since the motor needs the board’s GPIO pins to function.

Modules section

When you use a model from the Viam registry (not built into viam-server), your configuration includes a modules section that tells viam-server what to download:

FieldWhat it does
typeAlways "registry" for modules from the Viam registry.
nameA local name for the module (used in logs).
module_idThe registry identifier, in the form namespace:module-name.
versionThe version to use. Use a specific version for production; "latest" for development.

You don’t need to write this JSON by hand. When you add a module model through the Viam app, the modules section is created automatically.

Editing configuration

You can edit your machine’s configuration in two ways:

  • Builder UI: the visual editor in the Viam app. Best for adding components one at a time and using form fields for attributes.
  • JSON mode: click JSON in the left-hand menu on the CONFIGURE tab to see and edit the raw JSON. Best for copying configurations, making bulk changes, or understanding exactly what’s configured.

Both views edit the same underlying configuration. Changes in one are reflected in the other.

What’s next