Custom Fields
Attach your own data to a request so it shows up in your reports — for example an offer ID, a list name, or an internal campaign code. Custom fields are stored for reporting only and never change the risk score.
Two ways to send them
1. A named custom object (recommended)
{
"custom": {
"offer_id": "8842",
"list_name": "spring_push"
}
}2. Flat numbered slots
For integrations that can only add form parameters, not nested objects:
custom_1=8842 custom_2=spring_push
| Maximum fields | 10 per request |
| Key format | Lowercase, snake_case — mixed case and spaces are normalized automatically. |
| If you send both forms | A named key in custom wins over the matching numbered slot. |
Name your fields under your account's Profile settings so reports show readable column headers instead of custom_1, custom_2, etc.