The subscription resource is used to define a push based subscription from a server to another system. Once a subscription is registered with the server, the server checks every resource that is created or updated, and if the resource matches the given criteria, it sends a message on the defined "channel" so that another system is able to take an appropriate action. The subscription resource is used to define a push based subscription from a server to another system. Once a subscription is registered with the server, the server checks every resource that is created or updated, and if the resource matches the given criteria, it sends a message on the defined "channel" so that another system is able to take an appropriate action. If the element is present, it must have either a @value, an @id, or extensions The rules that the server should use to determine when to generate notifications for this subscription. Contact details for a human to contact about the subscription. The primary use of this for system administrator troubleshooting. A description of why this subscription is defined. The status of the subscription, which marks the server state for managing the subscription. A record of the last error that occurred when the server processed a notification. Details where to send notifications when resources are received that meet the criteria. The time for the server to turn the subscription off. A tag to add to any resource that matches the criteria, after the subscription is processed. The subscription resource is used to define a push based subscription from a server to another system. Once a subscription is registered with the server, the server checks every resource that is created or updated, and if the resource matches the given criteria, it sends a message on the defined "channel" so that another system is able to take an appropriate action. The type of channel to send notifications on. The uri that describes the actual end-point to send messages to. The mime type to send the payload in - either application/xml+fhir, or application/json+fhir. If the mime type is blank, then there is no payload in the notification, just a notification. Additional headers / information to send as part of the notification. The client has requested the subscription, and the server has not yet set it up. The subscription is active. The server has an error executing the notification. Too many errors have occurred or the subscription has expired. The status of a subscription. If the element is present, it must have either a @value, an @id, or extensions The channel is executed by making a post to the URI. If a payload is included, the URL is interpreted as the service base, and an update (PUT) is made. The channel is executed by sending a packet across a web socket connection maintained by the client. The URL identifies the websocket, and the client binds to this URL. The channel is executed by sending an email to the email addressed in the URI (which must be a mailto:). The channel is executed by sending an SMS message to the phone number identified in the URL (tel:). The channel is executed by sending a message (e.g. a Bundle with a MessageHeader resource etc.) to the application identified in the URI. The type of method used to execute a subscription. If the element is present, it must have either a @value, an @id, or extensions