Release 4 5 Preview #2
This page is part of the FHIR Specification (v4.0.1: R4 - Mixed Normative and STU ). This is the current published version in it's permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions
FHIR Infrastructure Work Group Maturity Level : N/A Standards Status : Informative Compartments : Not linked to any defined compartments

This is a representation of the json schema for Subscription, which is just a part of the full JSON Schema .

{
  "$schema": "http://json-schema.org/draft-06/schema#",
  "id": "http://hl7.org/fhir/json-schema/Subscription",
  "$ref": "#/definitions/Subscription",
  "description": "see http://hl7.org/fhir/json.html#schema for information about the FHIR Json Schemas",
  "definitions": {
    "Subscription": {
      "description": "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 can take an appropriate action.",

      "description": "The subscription resource describes a particular client\u0027s request to be notified about a SubscriptionTopic.",

      "properties": {
        "resourceType": {
          "description": "This is a Subscription resource",
          "const": "Subscription"
        },
        "id": {
          "description": "The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.",
          "$ref": "id.schema.json#/definitions/id"
        },
        "meta": {
          "description": "The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.",
          "$ref": "Meta.schema.json#/definitions/Meta"
        },
        "implicitRules": {
          "description": "A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.",
          "$ref": "#/definitions/uri"
        },
        "_implicitRules": {
          "description": "Extensions for implicitRules",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "language": {
          "description": "The base language in which the resource is written.",
          "$ref": "#/definitions/code"
        },
        "_language": {
          "description": "Extensions for language",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "text": {
          "description": "A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it \"clinically safe\" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.",
          "$ref": "Narrative.schema.json#/definitions/Narrative"
        },
        "contained": {
          "description": "These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.",
          "items": {
            "$ref": "ResourceList.schema.json#/definitions/ResourceList"
          },
          "type": "array"
        },
        "extension": {
          "description": "May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.",
          "items": {
            "$ref": "Extension.schema.json#/definitions/Extension"
          },
          "type": "array"
        },
        "modifierExtension": {
          "description": "May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element\u0027s descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.\n\nModifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).",
          "items": {
            "$ref": "Extension.schema.json#/definitions/Extension"
          },
          "type": "array"
        },
        "identifier": {
          "description": "A formal identifier that is used to identify this code system when it is represented in other formats, or referenced in a specification, model, design or an instance.",
          "items": {
            "$ref": "Identifier.schema.json#/definitions/Identifier"
          },
          "type": "array"
        },
        "name": {
          "description": "A natural language name identifying the subscription.",
          "$ref": "#/definitions/string"
        },
        "_name": {
          "description": "Extensions for name",
          "$ref": "Element.schema.json#/definitions/Element"
        },

        "status": {
          "description": "The status of the subscription, which marks the server state for managing the subscription.",
          "enum": [
            "requested",
            "active",
            "error",
            "off"
          ]

          "$ref": "#/definitions/code"

        },
        "_status": {
          "description": "Extensions for status",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "topic": {
          "description": "The reference to the subscription topic to be notified about.",
          "$ref": "Reference.schema.json#/definitions/Reference"
        },

        "contact": {
          "description": "Contact details for a human to contact about the subscription. The primary use of this for system administrator troubleshooting.",
          "items": {
            "$ref": "ContactPoint.schema.json#/definitions/ContactPoint"
          },
          "type": "array"
        },
        "end": {
          "description": "The time for the server to turn the subscription off.",
          "$ref": "#/definitions/instant"
        },
        "_end": {
          "description": "Extensions for end",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "reason": {
          "description": "A description of why this subscription is defined.",
          "$ref": "#/definitions/string"
        },
        "_reason": {
          "description": "Extensions for reason",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "criteria": {
          "description": "The rules that the server should use to determine when to generate notifications for this subscription.",
          "$ref": "#/definitions/string"

        "filterBy": {
          "description": "The filter properties to be applied to narrow the subscription topic stream.  When multiple filters are applied, evaluates to true if all the conditions are met; otherwise it returns false.   (i.e., logical AND).",
          "items": {
            "$ref": "#/definitions/Subscription_FilterBy"
          },
          "type": "array"

        },
        "_criteria": {
          "description": "Extensions for criteria",

        "channelType": {
          "description": "The type of channel to send notifications on.",
          "$ref": "Coding.schema.json#/definitions/Coding"
        },
        "endpoint": {
          "description": "The url that describes the actual end-point to send messages to.",
          "$ref": "#/definitions/url"
        },
        "_endpoint": {
          "description": "Extensions for endpoint",

          "$ref": "Element.schema.json#/definitions/Element"
        },
        "error": {
          "description": "A record of the last error that occurred when the server processed a notification.",
          "$ref": "#/definitions/string"

        "header": {
          "description": "Additional headers / information to send as part of the notification.",
          "items": {
            "$ref": "#/definitions/string"
          },
          "type": "array"

        },
        "_error": {
          "description": "Extensions for error",

        "_header": {
          "description": "Extensions for header",
          "items": {
            "$ref": "Element.schema.json#/definitions/Element"
          },
          "type": "array"
        },
        "heartbeatPeriod": {
          "description": "If present,  a \u0027hearbeat\" notification (keepalive) is sent via this channel with an the interval period equal to this elements integer value in seconds.    If not present, a heartbeat notification is not sent.",
          "$ref": "#/definitions/unsignedInt"
        },
        "_heartbeatPeriod": {
          "description": "Extensions for heartbeatPeriod",

          "$ref": "Element.schema.json#/definitions/Element"
        },
        "channel": {
          "description": "Details where to send notifications when resources are received that meet the criteria.",
          "$ref": "#/definitions/Subscription_Channel"

        "timeout": {
          "description": "If present, the maximum amount of time a server will allow before failing a notification attempt.",
          "$ref": "#/definitions/unsignedInt"
        },
        "_timeout": {
          "description": "Extensions for timeout",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "contentType": {
          "description": "The mime type to send the payload in - either application/fhir+xml, or application/fhir+json. The MIME types \"text/plain\" and \"text/html\" may also be used for Email subscriptions.",
          "$ref": "#/definitions/code"
        },
        "_contentType": {
          "description": "Extensions for contentType",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "content": {
          "description": "How much of the resource content to deliver in the notification payload. The choices are an empty payload, only the resource id, or the full resource content.",
          "enum": [
            "empty",
            "id-only",
            "full-resource"
          ]
        },
        "_content": {
          "description": "Extensions for content",
          "$ref": "Element.schema.json#/definitions/Element"

        }
      },
      "additionalProperties": false,
      "required": [
        "channel",

        "topic",
        "channelType",

        "resourceType"
      ]
    },
    "Subscription_Channel": {
      "description": "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 can take an appropriate action.",

    "Subscription_FilterBy": {
      "description": "The subscription resource describes a particular client\u0027s request to be notified about a SubscriptionTopic.",

      "properties": {
        "id": {
          "description": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
          "$ref": "string.schema.json#/definitions/string"
        },
        "extension": {
          "description": "May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.",
          "items": {
            "$ref": "Extension.schema.json#/definitions/Extension"
          },
          "type": "array"
        },
        "modifierExtension": {
          "description": "May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element\u0027s descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.\n\nModifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).",
          "items": {
            "$ref": "Extension.schema.json#/definitions/Extension"
          },
          "type": "array"
        },
        "type": {
          "description": "The type of channel to send notifications on.",
          "enum": [
            "rest-hook",
            "websocket",
            "email",
            "sms",
            "message"
          ]
        },
        "_type": {
          "description": "Extensions for type",
          "$ref": "Element.schema.json#/definitions/Element"
        },
        "endpoint": {
          "description": "The url that describes the actual end-point to send messages to.",
          "$ref": "#/definitions/url"

        "searchParamName": {
          "description": "The filter label (\u003dkey) as defined in the `SubscriptionTopic.canfilterBy.searchParamName`  element.",
          "$ref": "#/definitions/string"

        },
        "_endpoint": {
          "description": "Extensions for endpoint",

        "_searchParamName": {
          "description": "Extensions for searchParamName",

          "$ref": "Element.schema.json#/definitions/Element"
        },
        "payload": {
          "description": "The mime type to send the payload in - either application/fhir+xml, or application/fhir+json. If the payload is not present, then there is no payload in the notification, just a notification. The mime type \"text/plain\" may also be used for Email and SMS subscriptions.",

        "searchModifier": {
          "description": "The operator to apply to the filter value when determining matches (Search modifiers).",

          "$ref": "#/definitions/code"
        },
        "_payload": {
          "description": "Extensions for payload",

        "_searchModifier": {
          "description": "Extensions for searchModifier",

          "$ref": "Element.schema.json#/definitions/Element"
        },
        "header": {
          "description": "Additional headers / information to send as part of the notification.",
          "items": {
            "$ref": "#/definitions/string"
          },
          "type": "array"

        "value": {
          "description": "The literal value or resource path as is legal in search - for example, \"Patient/123\" or \"le1950\".",
          "$ref": "#/definitions/string"

        },
        "_header": {
          "description": "Extensions for header",
          "items": {
            "$ref": "Element.schema.json#/definitions/Element"
          },
          "type": "array"

        "_value": {
          "description": "Extensions for value",
          "$ref": "Element.schema.json#/definitions/Element"

        }
      },
      "additionalProperties": false
    }
  }
}