Response Events

When you handle an Alexa directive successfully, respond with a response event. The most generic response event is Alexa.Response. Some directives have more specific response events, for example, an Add directive might have an AddResponse response event. Check the documentation for your specific interface and directive to determine the correct response event to use.

If you can't handle a directive successfully, respond with an Alexa.ErrorResponse event instead.

Types of responses

When you handle an Alexa directive successfully, respond with a response event. You can respond in one of the following ways:

Usually, Alexa waits eight seconds for your response before timing out. For devices that make physical changes that take longer, such as a lock, you might have to send a deferred response before you send your regular response. For details, see deferred response.

In the context object of your response, include the values of all the properties of the endpoint that changed and the time of the change. You also include the values of properties that didn't change, to give Alexa the complete current state of the endpoint.

All response messages should include a correlation token.

Synchronous response

Check the documentation for your specific interface to determine the correct response properties to the Alexa directive.

Synchronous response example

The following example shows a standard synchronous response. In this example, the endpoint supports the Alexa.PowerController interface and the TurnOn directive.

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{
  "event": {
    "header": {
      "namespace": "Alexa",
      "name": "Response",
      "messageId": "a unique identifier, preferably a version 4 UUID",
      "correlationToken": "an opaque correlation token that matches the request",
      "payloadVersion": "3"
    },
    "endpoint": {
      "endpointId": "endpoint ID"
    },
    "payload": {}
  },
  "context": {
    "properties": [
      {
        "namespace": "Alexa.PowerController",
        "name": "powerState",
        "value": "ON",
        "timeOfSample": "2017-02-03T16:20:50.52Z",
        "uncertaintyInMilliseconds": 500
      }
    ]
  }
}

Asynchronous response

When you respond asynchronously, you send an HTTP request to the Alexa event gateway. In the request body, you include the response event. Your response must include the access token that authenticates your skill customer to Alexa.

Asynchronous response example

The following example shows an asynchronous response. In this example, the endpoint supports the Alexa.ColorTemperatureController interface.

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POST /v3/events HTTP/1.1
Host: api-amazonalexa.com
Authorization: Bearer access-token-from-Amazon
Content-Type: application/json
{
  "event": {
    "header": {
      "namespace": "Alexa",
      "name": "Response",
      "messageId": "a unique identifier, preferably a version 4 UUID",
      "correlationToken": "an opaque correlation token that matches the request",
      "payloadVersion": "3"
    },
    "endpoint": {
      "scope": {
        "type": "BearerToken",
        "token": "access-token-from-Amazon"
      },
      "endpointId": "endpoint ID"
    },
    "payload": {}
  },
  "context": {
    "properties": [
      {
        "namespace": "Alexa.ColorTemperatureController",
        "name": "colorTemperatureInKelvin",
        "value": 5500,
        "timeOfSample": "2017-02-03T16:20:50.52Z",
        "uncertaintyInMilliseconds": 500
      }
    ]
  }
}

Asynchronous response event properties

Check the documentation for your specific interface and directive to determine the correct response properties.

Alexa response to the asynchronous response event

On success, Alexa sends 202 Accepted to indicate that the event was accepted for further logical validation and processing. If the event isn't accepted, Alexa sends the appropriate HTTP status code.

Response body parameters

The response has no body.

HTTP status codes

The following table shows the HTTP status code values that your skill might receive from the Alexa event gateway. If you receive an error, the payload object contains a code and description field. Use these fields for logging only.

Status Payload code Description

202 Accepted

—

Request is authorized and the message is a syntactically valid event. The event was accepted for further logical validation and processing.

400 Bad Request

INVALID_REQUEST_EXCEPTION

Message is invalid due to missing fields, incorrect values, or malformed JSON. Check your messages against the documentation to verify that your message contains all the required fields.

401 Unauthorized

INVALID_ACCESS_TOKEN_EXCEPTION

Message didn't include the authorization token or the token is invalid, expired, or malformed. Refresh your token and retry the request. If a user disables your skill, that also invalidates the access token. Here, the user revoked authorization, and you can stop sending change reports for them.

403 Forbidden

SKILL_NEVER_ENABLED_EXCEPTION

You're not allowed access to the event gateway. Make sure that you're sending the events to the correct regional endpoint. For example, send events in North America to the North American endpoint.

403 Forbidden

INSUFFICIENT_PERMISSION_EXCEPTION

Token doesn't have the required permissions. Make sure that the skill has permission to send Alexa events. For details, see Request Access to the Alexa Event Gateway.

404 Not Found

ACCOUNT_NOT_FOUND_EXCEPTION

Account record associated with this directed identifier doesn't exist or has expired. This error can occur if the event was sent too late or with an invalid directed identifier. Verify that the directed identifier and authorization code are correct.

404 Not Found

SKILL_NOT_FOUND_EXCEPTION

Skill ID associated with this token wasn't found. This error occurs when user's access token was generated when the skill was in different stage, such as certification. Try disabling and re-enabling the skill for this user.

413 Payload Too Large

REQUEST_ENTITY_TOO_LARGE_EXCEPTION

Size of the event payload is too large. The maximum number of endpoints allowed in a request is 300. Send your message with smaller payloads.

429 Too Many Requests

THROTTLING_EXCEPTION

Number of requests is too high. Resend the message up to three times, with at least a one-second interval between each send attempt.

500 Internal Server Error

INTERNAL_SERVICE_EXCEPTION

Error occurred with Alexa, and the message wasn't processed. Resend the message up to three times, with at least a one-second interval between each send attempt. If problems persist, contact Amazon Support.

503 Service Unavailable

SERVICE_UNAVAILABLE_EXCEPTION

Alexa couldn't accept the message. Resend the message up to three times, with at least a one-second interval between each attempt. If the problem persists, contact Amazon Support.

Example 401 Unauthorized response body

The following example shows an error response.

HTTP/1.1 400 Bad Request
Date: Wed, 07 Mar 2018 20:25:31 GMT
Connection: close

{
  "header": {
    "namespace": "System",
    "name": "Exception",
    "messageId": "90c3fc62-4b2d-460c-9c8b-77251f1698a0"
  },
  "payload": {
      "code": "INVALID_ACCESS_TOKEN_EXCEPTION",
      "description": "The access token is invalid, expired, or malformed."
  }
}

DeferredResponse

Usually, Alexa waits for your response for eight seconds before timing out. Exceptions are noted in the documentation for individual interfaces. If your response takes more than eight seconds, first send a synchronous DeferredResponse event, and then follow it with a Response event, either synchronous or asynchronous.

DeferredResponse is only supported for some interfaces, for example Alexa.LockController. Check the documentation for your specific interface to determine if DeferredResponse is supported.

Because you always send a DeferredResponse synchronously, don't include a scope.

DeferredResponse event payload

Field Description Type Required
estimatedDeferralInSeconds The approximate time before you send your second response, in seconds. Integer No

DeferredResponse example

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{
  "event": {
    "header": {
      "namespace": "Alexa",
      "name": "DeferredResponse",
      "messageId": "a unique identifier, preferably a version 4 UUID",
      "correlationToken": "an opaque correlation token that matches the request",
      "payloadVersion": "3"
    },
    "payload": {
      "estimatedDeferralInSeconds": 7
    }
  }
}