Build on 9ID

# 1. get an access token
curl -X POST https://auth.nineid.cloud/auth/app-oauth \
  -d grant_type=client_credentials \
  -d client_id=YOUR_CLIENT_ID \
  -d client_secret=YOUR_CLIENT_SECRET

# 2. list users
curl "https://YOUR_TENANT.nineid.cloud/api/external/v2/users" \
  -H "Authorization: Bearer ACCESS_TOKEN"

# 9ID posts this to your URL
{
  "event": "user.created",
  "timestamp": "2026-10-09T09:30:00.000Z",
  "data": { ... }
}