Alexa.InventoryLevelSensor Interface 3

Implement the Alexa.InventoryLevelSensor interface in your Alexa skill so that you can report the amount of a consumable product that your device has remaining. For example, if your device is a printer, you can report the amount of ink or toner that the printer has remaining. You can implement multiple instances of Alexa.InventoryLevelSensor for multiple consumable products, such as a printer with separate storage for cyan, yellow, magenta, and black ink or toner.

If you report when your device uses a consumable product, implement the Alexa.InventoryUsageSensor interface instead. If the consumable product that you track has an unknown lifespan, implement the Alexa.InventoryLevelUsageSensor interface instead.

For the list of languages that the Alexa.InventoryLevelSensor interface supports, see List of Alexa Interfaces and Supported Languages. For the definitions of the message properties, see Alexa Interface Message and Property Reference.

Dash replenishment IDs

You can add the Amazon Dash Replenishment Service to your smart home device to enable Alexa to monitor and reorder supplies or replacement parts for your device. When you report inventory with Alexa.InventoryLevelSensor, your customers can track supply levels within the Alexa app and receive notifications from Alexa when supplies run low or parts need replacement. Also, customers can set up automatic reordering of these supplies. For example, a printer can report ink usage to Alexa so that the customer doesn't run out of ink. For details, see About Dash Replenishment.

When you register your device for Dash replenishment, Amazon supplies a replenishment ID for each consumable product in your device. The replenishment ID identifies the products that the customer can order to replace the consumed product. You can provide these IDs to Alexa in the following ways:

  • If you already have your replenishment IDs at the time of device discovery, provide them in your discovery response.
  • If you don't have the replenishment IDs at the time of device discovery, provide your replenishment IDs later in an AddOrUpdateReport event.

Properties and objects

The Alexa.InventoryLevelSensor interface includes the following properties and objects.

Reportable properties

The Alexa.InventoryLevelSensor interface defines the level property as the primary property. You identify the properties that you support in your discovery response.

The level property represents the current amount of a consumable product that a device has remaining. You can express level as one of the following types: count, percentage, volume, or weight. For volume and weight, you include the unit of measure.

Measurement object

The Measurement object defines the way that you measure a consumable product.

Property Description Type

@type

Measurement type.
Valid values: count, percentage, volume, weight.

String

value

Current level of the consumable product. Include when you report the usage.

String

unit

Standard of measurement for the type. Include for volume and weight only. For valid values, see volume units and weight units.

String

Replenishment object

The Replenishment object identifies the consumable product.

Property Description Type

@type

Identifies the ID type.
Valid values: DashReplenishmentId.

String

value

Dash replenishment ID for the consumable product.
You request replenishment IDs in the Dash console.

String

Discovery

You describe endpoints that support Alexa.InventoryLevelSensor by using the standard discovery mechanism described in Alexa.Discovery.

Set proactivelyReported to true for the properties that you proactively report to Alexa in a change report.

An endpoint can support multiple sensors. To distinguish sensors, you must include the an Alexa.InventoryLevelSensor with the instance property for each sensor that you support.

For the full list of display categories, see display categories.

To let Alexa know the health of your device, also implement the Alexa.EndpointHealth interface.

Capabilities array

In addition to the usual discovery response fields, for each Alexa.InventoryLevelSensor entry in the capabilities array, include the following fields.

Property Description Type

instance

Name of the sensor.
Examples: Ink.Cyan or Ink.Yellow.

String

configuration.measurement

Way you measure the consumable product.

Measurement object

configuration.replenishment

Dash replenishment ID for the consumable product.

Replenishment object

capabilityResources

Friendly names for the consumable product that customers can use to interact with the sensor.

CapabilityResources object

Discover response example

The following example shows a Discover.Response message for a printer that supports the Alexa.InventoryLevelSensor interface.

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{
  "event": {
    "header": {
      "namespace": "Alexa.Discovery",
      "name": "Discover.Response",
      "payloadVersion": "3",
      "messageId": "Unique identifier, preferably a version 4 UUID"
    },
    "payload": {
      "endpoints": [
        {
          "endpointId": "Unique ID of the endpoint",
          "manufacturerName": "Printer Plus",
          "description": "Smart Printer by Printer Maker Plus",
          "friendlyName": "Printer",
          "displayCategories": [
            "OTHER"
          ],
          "cookie": {},
          "capabilities": [
            {
              "type": "AlexaInterface",
              "interface": "Alexa.InventoryLevelSensor",
              "instance": "InkSensor.Cyan",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "level"
                  }
                ],
                "retrievable": false,
                "proactivelyReported": true
              },
              "configuration": {
                "measurement": {
                  "@type": "Volume",
                  "unit": "MILLILITER"
                },
                "replenishment": {
                  "@type": "DashReplenishmentId",
                  "value": "replenishment ID for refill options"
                }
              },
              "capabilityResources": {
                "friendlyNames": [
                  {
                    "@type": "text",
                    "value": {
                      "text": "Cyan ink",
                      "locale": "en-US"
                    }
                  },
                  {
                    "@type": "text",
                    "value": {
                      "text": "Encre cyan",
                      "locale": "fr-FR"
                    }
                  }
                ]
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa.InventoryLevelSensor",
              "instance": "PaperSensor.FrontTray",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "level"
                  }
                ],
                "retrievable": false,
                "proactivelyReported": true
              },
              "configuration": {
                "measurement": {
                  "@type": "Count"
                },
                "replenishment": {
                  "@type": "DashReplenishmentId",
                  "value": "replenishment ID for refill options"
                }
              },
              "capabilityResources": {
                "friendlyNames": [
                  {
                    "@type": "text",
                    "value": {
                      "text": "Front tray",
                      "locale": "en-US"
                    }
                  }
                ]
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa.PowerController",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "powerState"
                  }
                ],
                "retrievable": true,
                "proactivelyReported": true
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa.EndpointHealth",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "connectivity"
                  }
                ],
                "proactivelyReported": true,
                "retrievable": true
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa",
              "version": "3"
            }
          ]
        }
      ]
    }
  }
}

AddOrUpdateReport

You must proactively send an Alexa.Discovery.AddOrUpdateReport event if the feature support of your endpoint changes. For example, if you don't have the replenishment IDs for your consumable products at the time of initial device discovery, you can provide the replenishment IDs to Alexa later by sending an AddOrUpdateReport event. You can't change the replenishment IDs after you report them the first time.

AddOrUpdateReport event example

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{
  "event": {
    "header": {
      "namespace": "Alexa.Discovery",
      "name": "AddOrUpdateReport",
      "payloadVersion": "3",
      "messageId": "Unique identifier, preferably a version 4 UUID"
    },
    "payload": {
      "endpoints": [
        {
          "endpointId": "Unique ID of the endpoint",
          "manufacturerName": "Printer Plus",
          "description": "Smart Printer by Printer Maker Plus",
          "friendlyName": "Printer",
          "displayCategories": [
            "OTHER"
          ],
          "cookie": {},
          "capabilities": [
            {
              "type": "AlexaInterface",
              "interface": "Alexa.InventoryLevelSensor",
              "instance": "InkSensor.Cyan",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "level"
                  }
                ],
                "retrievable": true,
                "proactivelyReported": true
              },
              "configuration": {
                "measurement": {
                  "@type": "Volume",
                  "unit": "MILLILITER"
                },
                "replenishment": {
                  "@type": "DashReplenishmentId",
                  "value": "replenishment ID for refill options"
                }
              },
              "capabilityResources": {
                "friendlyNames": [
                  {
                    "@type": "text",
                    "value": {
                      "text": "Cyan ink",
                      "locale": "en-US"
                    }
                  },
                  {
                    "@type": "text",
                    "value": {
                      "text": "Encre cyan",
                      "locale": "fr-FR"
                    }
                  }
                ]
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa.InventoryLevelSensor",
              "instance": "PaperSensor.FrontTray",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "level"
                  }
                ],
                "retrievable": true,
                "proactivelyReported": true
              },
              "configuration": {
                "measurement": {
                  "@type": "Count"
                },
                "replenishment": {
                  "@type": "DashReplenishmentId",
                  "value": "replenishment ID for refill options"
                }
              },
              "capabilityResources": {
                "friendlyNames": [
                  {
                    "@type": "text",
                    "value": {
                      "text": "Front tray",
                      "locale": "en-US"
                    }
                  }
                ]
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa.PowerController",
              "version": "3",
              "properties": {
                "supported": [
                  {
                    "name": "powerState"
                  }
                ],
                "retrievable": true,
                "proactivelyReported": true
              }
            },
            {
              "type": "AlexaInterface",
              "interface": "Alexa",
              "version": "3"
            }
          ]
        }
      ]
    }
  }
}

Change reporting

To report inventory proactively to Alexa, you send a ChangeReport event and include the remaining levels of each consumable product. You identify the properties that you proactively report in your discovery response. For details about change reports, see Understand State and Change Reporting.

ChangeReport event example

In the following example, you notify Alexa about the remaining levels of each consumable product after a daily check of all sensors.

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{  
  "event": {
    "header": {
      "namespace": "Alexa",
      "name": "ChangeReport",
      "messageId": "Unique identifier, preferably a version 4 UUID",
      "payloadVersion": "3"
    },
    "endpoint": {
      "scope": {
        "type": "BearerToken",
        "token": "OAuth2.0 bearer token"
      },
      "endpointId": "Endpoint ID"
    },
    "payload": {
      "change": {
        "cause": {
          "type": "PERIODIC_POLL"
        },
        "properties": [
          {
            "namespace": "Alexa.InventoryLevelSensor",
            "instance": "InkSensor.Cyan",
            "name": "level",
            "value": {
              "@type": "Volume",
              "value": 5,
              "unit": "MILLILITER"
            },
            "timeOfSample": "2019-10-31T17:00:00Z",
            "uncertaintyInMilliseconds": 0
          },
          {
            "namespace": "Alexa.InventoryLevelSensor",
            "instance": "PaperSensor.FrontTray",
            "name": "level",
            "value": {
              "@type": "Count",
              "value": 200
            },
            "timeOfSample": "2019-10-31T17:00:00Z",
            "uncertaintyInMilliseconds": 0
          },
          {
            "namespace": "Alexa.PowerController",
            "name": "powerState",
            "value": "ON",
            "timeOfSample": "2019-10-31T17:00:00Z",
            "uncertaintyInMilliseconds": 0
          }
        ]
      }
    }
  },
  "context": {
    "namespace": "Alexa.EndpointHealth",
    "name": "connectivity",
    "value": {
      "value": "OK"
    },
    "timeOfSample": "2019-10-31T17:00:00Z",
    "uncertaintyInMilliseconds": 0
  }
}
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Last updated: Sep 13, 2023