This is one of many protocol behaviors described in ActivityPub.

Identifier

urn:uuid:00330762-59a2-4072-8d93-87ee4c30411c

Content

Servers... unless the activity is transient, MUST include the new id in the Location header.

Origin

prefix Servers MUST return a 201 Created HTTP code, and

unless the activity is transient, MUST include the new id in the Location header.
 
suffix Example 12: Outbox response to submitted Activity

https://www.w3.org/TR/activitypub/

JSON

{
  "id": "urn:uuid:00330762-59a2-4072-8d93-87ee4c30411c",
  "type": "Behavior",
  "uuid": "00330762-59a2-4072-8d93-87ee4c30411c",
  "content": "Servers... unless the activity is transient, MUST include the new id in the Location header.",
  "context": [
    "https://www.w3.org/TR/activitypub/",
    {
      "name": "Client to server interaction"
    },
    {
      "name": "server responding to client posting Activities to an actor's outbox"
    }
  ],
  "origin": {
    "source": "https://www.w3.org/TR/activitypub/",
    "selector": {
      "type": "TextQuoteSelector",
      "prefix": "Servers MUST return a 201 Created HTTP code, and \n",
      "exact": "unless the activity is transient, MUST include the new id in the Location header.\n",
      "suffix": "Example 12: Outbox response to submitted Activity\n"
    },
    "section": {
      "id": "https://www.w3.org/TR/activitypub/#x6-client-to-server-interactions",
      "branch": [
        6
      ]
    }
  },
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://socialweb.coop/ns/testing/context.json"
  ]
}