We allow you to send custom fields in any of our events, as well as any in custom events you make.  Here are some tips for sending custom fields:

1. You can include them in any event you send, but not inside any of our complex fields (address, item, payment method).
   
   
2. Custom fields with the same name overwrite each other. 
   
   To capture the count of something, like how many vouchers a user has redeemed, use a custom field and send us that value as an integer.
   
   Note: A custom field with the same name in two separate events is considered the same field, and the latest value from the latest event sent is used in scoring.
   
   For example:
   
   In a place_bid event: "user_account_balance" : 40000000 ($40.00). In the subsequent $transaction event after the item is won and purchased: "user_account_balance" : 30000000 ($30.00). In other cases, when the field is related to the event and not the user identifier, it makes sense to give them unique names to capture the difference.  For example, if your website sells train and airplane tickets: In a $create_order event: "plane_seat_class" : "business", "train_seat_class" : "business"
3. We look at the rate of custom events sent.
   
   To capture risky activity users perform that isn't covered by our reserved events use a custom event or use a custom field where you send us the rate or total as an integer. For example, send a "place_bid" event.  Or, on the event you check the score (like $create_order), send a field to record the activity, e.g. "bids_placed" : 3
   
   
4. To capture a value that describes a category, like the type of account a user has (standard, premium), use a custom field where you send that value as a string.
   
   For example: "product_tier" : "premium"
   
   See more examples of how to send values here.