# SubscriptionChannel

An notification channel used to watch for resource changes.

| JSON representation |
|---|
| ``` { "id": string, "token": string, "expiration": string, "type": string, "address": string, "payload": boolean, "params": { string: string, ... }, "resourceId": string, "resourceUri": string, "kind": string } ``` |

| Fields ||
|---|---|
| `id` | `string` A UUID or similar unique string that identifies this channel. |
| `token` | `string` An arbitrary string delivered to the target address with each notification delivered over this channel. Optional. |
| `expiration` | `string (https://developers.google.com/discovery/v1/type-format format)` Date and time of notification channel expiration, expressed as a Unix timestamp, in milliseconds. Optional. |
| `type` | `string` The type of delivery mechanism used for this channel. |
| `address` | `string` The address where notifications are delivered for this channel. |
| `payload` | `boolean` A Boolean value to indicate whether payload is wanted. Optional. |
| `params` | `map (key: string, value: string)` Additional parameters controlling delivery channel behavior. Optional. For example, `params.ttl` specifies the time-to-live in seconds for the notification channel, where the default is 2 hours and the maximum TTL is 2 days. An object containing a list of `"key": value` pairs. Example: `{ "name": "wrench", "mass": "1.3kg", "count": "3" }`. |
| `resourceId` | `string` An opaque ID that identifies the resource being watched on this channel. Stable across different API versions. |
| `resourceUri` | `string` A version-specific identifier for the watched resource. |
| `kind` | `string` Identifies this as a notification channel used to watch for changes to a resource, which is `api#channel`. |