I'm trying to create an EventRelation using the REST API, but it does not seem to be working. Here are the details of the request:

URI: /services/data/v37.0/sobjects/EventRelation/

With the following in the body of the request:

EventId: xxx (ID of the event I want to add a relation to)

RelationId: xxx (ID of a specific contact)

The API doesn't create the EventRelation and just returns the following:

  "objectDescribe": {
    "activateable": false,
    "createable": true,
    "custom": false,
    "customSetting": false,
    "deletable": true,
    "deprecatedAndHidden": false,
    "feedEnabled": false,
    "keyPrefix": "0RE",
    "label": "Event Relation",
    "labelPlural": "Event Relations",
    "layoutable": false,
    "mergeable": false,
    "mruEnabled": false,
    "name": "EventRelation",
    "queryable": true,
    "replicateable": true,
    "retrieveable": true,
    "searchable": false,
    "triggerable": false,
    "undeletable": false,
    "updateable": true,
    "urls": {
      "rowTemplate": "/services/data/v37.0/sobjects/EventRelation/{ID}",
      "defaultValues": "/services/data/v37.0/sobjects/EventRelation/defaultValues?recordTypeId&fields",
      "describe": "/services/data/v37.0/sobjects/EventRelation/describe",
      "sobject": "/services/data/v37.0/sobjects/EventRelation"
  "recentItems": [

Is there something I'm doing wrong? Am I not passing required fields? I simply just want to attach a lead or contact to an event.

  • Are you setting the method as POST instead of GET?
    – Adrian Larson
    Jun 29, 2017 at 15:51

1 Answer 1


Sounds to me like you just specified GET instead of POST as the method. That returns the describe, instead of trying to create a record. Make sure you set your method to POST.


Notice how the API is clearly trying to create a record here:

POST Results


Here, the API returns the describe:

GET Results

  • Ah this makes so much sense thanks! I'm now getting the error "The HTTP entity body is required, but this request has no entity body." which is strange because I am passing the EventId and RelationId in the body, any thoughts? Jun 29, 2017 at 16:03
  • @ChrisSchlitt I would create a new question for that and share the actual code you use to make the callout.
    – Adrian Larson
    Jun 29, 2017 at 16:14

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