Alexa.Authorization Interface 3

Implement the Alexa.Authorization interface in your Alexa skill to give your skill access to the Alexa event gateway. Access to the gateway enables you to send asynchronous responses and proactive events, such as Alexa.ChangeReport, to Alexa.

For the definitions of the message properties, see Alexa Interface Message and Property Reference.

Event gateway authorization

The purpose of the Alexa.Authorization.AcceptGrant directive is to enable you to obtain credentials that identify and authenticate a customer to Alexa.

Alexa sends an AcceptGrant directive after a customer enables a smart home skill and goes through the account linking process, or when you update an existing smart home skill to support proactive events.

The AcceptGrant directive contains the following information:

  • Alexa sends you an authorization code. Exchange the authorization code for an access token and refresh token by using Login With Amazon (LWA). For details, see the LWA documentation.

  • Alexa sends you the access token for the customer that Alexa received during the account linking process. Store the token, and use the token to identify the customer in your system.

Directives

The Alexa.Authorization interface defines the following directives.

AcceptGrant directive

Support the AcceptGrant directive so that you can obtain and store credentials that identify a customer to Alexa.

AcceptGrant directive example

The following example illustrates an AcceptGrant directive that Alexa sends to your skill. Because this interface is synchronous, the message doesn't contain a correlation token.

{
  "directive": {
    "header": {
      "namespace": "Alexa.Authorization",
      "name": "AcceptGrant",
      "messageId": "Unique version 4 UUID",
      "payloadVersion": "3"
    },
    "payload": {
      "grant": {
        "type": "OAuth2.AuthorizationCode",
        "code": "someAuthCode"
      },
      "grantee": {
        "type": "BearerToken",
        "token": "someAccessToken"
      }
    }
  }
}

AcceptGrant directive payload

The following table shows the payload details for the AcceptGrant directive.

Property Description Type Required

grant

Information that identifies a customer in Amazon Alexa systems.

Object

Yes

grant.type

Type of grant.
Valid value: OAuth2.AuthorizationCode.

String

Yes

grant.code

Authorization code for the customer.
Exchange the authorization code for an access token and refresh token by using the Login With Amazon (LWA) OAuth 2.0 server.

String

Yes

grantee

Information that identifies a customer in the linked-account service or system.

Object

Yes

grantee.type

Type of grantee.
Valid value: BearerToken.

String

Yes

grantee.token

The customer access token received by Alexa during the account linking process.

String

Yes

AcceptGrant response

If you handle an AcceptGrant directive successfully, respond with an AcceptGrant.Response. Because this interface is synchronous only, don't include a correlation token.

The following example shows a AcceptGrant.Response. The response doesn't require a payload.

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{
  "event": {
    "header": {
      "namespace": "Alexa.Authorization",
      "name": "AcceptGrant.Response",
      "messageId": "Unique identifier, preferably a version 4 UUID",
      "payloadVersion": "3"
    },
    "payload": {}
  }
}

AcceptGrant error handling

If you can't handle an AcceptGrant directive successfully for one of the following reasons, respond with an Alexa.Authorization.ErrorResponse:

  • You're unable to call LWA to exchange the authorization code for access and refresh tokens.
  • You're unable to store the access and refresh tokens for the customer.
  • Any other error that occurs while you try to retrieve and store the access and refresh tokens.

For more general errors, respond with an Alexa.ErrorResponse event.

The following example shows an Alexa.Authorization.ErrorResponse.

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{
  "event": {
    "header": {
      "messageId": "Unique identifier, preferably a version 4 UUID",
      "namespace": "Alexa.Authorization",
      "name": "ErrorResponse",
      "payloadVersion": "3"
    },
    "payload": {
      "type": "ACCEPT_GRANT_FAILED",
      "message": "Failed to handle the AcceptGrant directive because <your reason>"
    }
  }
}