Create Webinar Registrant

• email: Email address of the registrant. Must be unique per event.
• first_name: Registrant’s first name.
• last_name: Registrant’s last name.
• custom_fields: List of custom registration fields. Each item holds the field label (the custom field name) and the submitted value.

  Notes:

  • email, first_name & last_name are always mandatory for every webinar.
  • Rest of parameters are mandatory only if defined so in the registration form setup when scheduling the event.
  • phonefield: phone number in international format, separated to country code and phone number.
  • text field limited to 256 characters.
  • checkboxfield: limited to TRUE or FALSE

• 200 OK Registration created successfully. 401 Unauthorized Authentication failed (Invalid or missing API token).
• 403 Forbidden The event belongs to another account.
• 404 Not Found Event not found.
• 409 Conflict Duplicate registration (a registrant with the same email already exists for this event), or the on-demand webinar is not published.
• 422 Unprocessable EntityValidation error (for example, invalid email format, unsupported country code, or invalid custom_fields payload).

​

On-Demand Webinars

Notes:

• Registration is allowed only for published on-demand webinars. Registering to an unpublished webinar returns 409 Conflict.
• While a webinar is unpublished, its public page — including previously issued join_url links — returns 404. Republishing restores those links, and registrants do not need to register again.
• join_url is the registrant’s personalized, tokenized watch URL. Opening it lands the registrant directly on the player, skipping the registration form.
• Riverside sends no emails for on-demand registrations, whether created through the API or the registration form. Delivery of the watch link is owned by you.
• Registrants created through the API return referrer: "api" in Get Registrants, and are otherwise indistinguishable from form registrants across the registrants list, counts, engagement analytics and CRM sync.
• Watch activity through the link is attributed to the created registrant, and is reflected in the participated, attendance_rate and duration fields of Get Registrants.
• There is no registrant cap for on-demand webinars.

​

Sample Request

POST /api/v3/events/123/registrants HTTP/1.1
Host: platform.riverside.com
Authorization: BEARER YOUR_API_KEY

{
  "email": "[email protected]",
  "first_name": "Ada",
  "last_name": "Lovelace",
  "custom_fields":  [
	{
      "label": "how many webinars did you attend?",
      "value": "one"
    },
    {
      "label": "Country",
      "value": "United States"
    },
    {
      "label": "Phone",
      "value": {"countryCode":"+1","phoneNumber":"555555555"}
    },
    {
      "label": "Do you agree to be contacted?",
      "value": true
    },
    {
      "label": "Question",
      "value": "Answer 1"
    }
  ]
}

​

Sample Response

{
  "event_id": "ev_456",
  "join_url": "https://riverside.fm/webinar/ev_456?token=abc123..."
}

​

Error Responses

{
  "statusCode": 409,
  "message": "Email already registered for this event"
}

{
  "statusCode": 409,
  "message": "Webinar is not published"
}

{
  "statusCode": 422,
  "message": "Validation failed",
  "errors": [
    {
      "field": "email",
      "message": "Invalid email format"
    }
  ]
}

{
  "statusCode": 404,
  "message": "Event not found"
}