How to update a participant's External ID

Use this guide when you need to set or change the External ID stored against a participant — for example, when migrating from one external system to another, or when assigning a system identifier after the account was initially created without one.

Prerequisites

Your API key
The participant's internal id or email to identify the account (since you may not yet have an External ID for them)

Request — set External ID using internal ID

Bash

curl -X POST "https://your-event-domain.com/api/v2/account/set" \
  -H "Authorization: Bearer your_api_key_here" \
  -F "event_id=7" \
  -F "id=12345" \
  -F "external_id=EXT-00123"

Request — set External ID using email

Bash

curl -X POST "https://your-event-domain.com/api/v2/account/set" \
  -H "Authorization: Bearer your_api_key_here" \
  -F "event_id=7" \
  -F "email=john.doe@example.com" \
  -F "external_id=EXT-00123"

Response

JSON

{
  "code": 200,
  "errors": null,
  "data": {
    "id": 12345,
    "email": "john.doe@example.com",
    "status": "updated",
    "external_id": "EXT-00123",
    "info": ["Account match: id"],
    "errors": []
  },
  "response_id": "1700000000.12345"
}

The external_id field in the response confirms the new value was stored.

Notes

Once set, the External ID can be used as the lookup key in all future requests
External IDs are stored as strings — maintain consistent formatting in your system
If you pass external_id as a lookup key in the same request where you're trying to change it, the endpoint will attempt to find a match on the current (old) value first