Returns user-defined custom column (derived metric) definitions.

Returns the list of custom columns configured for this account. Custom columns are user-defined derived metrics with formulas (e.g. calculated EPC variants, margin formulas, blended scores).

Relationship to reports

Each custom column has a name that can be passed directly as a column value in report API calls, alongside built-in metrics like visits or roi.

Usage

Call this endpoint at startup and append all custom column names to your default report column set. Accounts with active custom columns will produce incomplete analysis if these are excluded — they may represent the primary metrics the user cares about.