This is a sample of the request sent to a webhook when using a Google Assistant device with speech. In this case, it was a Home Mini.

dialogflow-sample-request.json

{
    "originalRequest": {
        "source": "google",
        "version": "2",
        "data": {
            "isInSandbox": true,
            "surface": {
                "capabilities": [
                    {
                        "name": "actions.capability.AUDIO_OUTPUT"
                    },
                    {
                        "name": "actions.capability.MEDIA_RESPONSE_AUDIO"
                    }
                ]
            },
            "inputs": [
                {
                    "rawInputs": [
                        {
                            "query": "talk to bertons open Fass",
                            "inputType": "VOICE"
                        }
                    ],
                    "intent": "actions.intent.MAIN"
                }
            ],
            "user": {
                "lastSeen": "2018-01-06T22:41:26Z",
                "locale": "en-US",
                "userId": "--YOUR USER ID HASH--"
            },
            "conversation": {
                "conversationId": "1515278922957",
                "type": "NEW"
            },
            "availableSurfaces": [
                {
                    "capabilities": [
                        {
                            "name": "actions.capability.SCREEN_OUTPUT"
                        },
                        {
                            "name": "actions.capability.AUDIO_OUTPUT"
                        }
                    ]
                }
            ]
        }
    },
    "id": "c4f945db-4a9a-4dda-85f6-532d291afcbd",
    "timestamp": "2018-01-06T22:48:43.007Z",
    "lang": "en-us",
    "result": {
        "source": "agent",
        "resolvedQuery": "GOOGLE_ASSISTANT_WELCOME",
        "speech": "",
        "action": "input.welcome",
        "actionIncomplete": false,
        "parameters": {},
        "contexts": [
            {
                "name": "google_assistant_welcome",
                "parameters": {},
                "lifespan": 0
            },
            {
                "name": "google_assistant_input_type_voice",
                "parameters": {},
                "lifespan": 0
            },
            {
                "name": "actions_capability_audio_output",
                "parameters": {},
                "lifespan": 0
            },
            {
                "name": "actions_capability_media_response_audio",
                "parameters": {},
                "lifespan": 0
            }
        ],
        "metadata": {
            "intentId": "f2394fa2-72b5-4e2c-876b-022508884904",
            "webhookUsed": "true",
            "webhookForSlotFillingUsed": "true",
            "nluResponseTime": 0,
            "intentName": "default welcome"
        },
        "fulfillment": {
            "speech": "",
            "messages": []
        },
        "score": 1
    },
    "status": {
        "code": 200,
        "errorType": "success",
        "webhookTimedOut": false
    },
    "sessionId": "1515278922957"
}