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JustOn Tax Handling

Depending on your business requirements and your system environment, JustOn can handle taxes in various ways:

Internal Tax Calculation

By default, JustOn calculates the tax for each invoice line item based on its tax rate. This tax rate can either be a fix value (set as product tax rate) or be determined using tax rules, as outlined below.


Note that you can combine the two approaches. JustOn first tries to evaluate tax rules, and in case there are no matching rules or none at all, the specified product tax rate is used.

When using JustOn's internal tax calculation with a fix tax rate or tax rules, you can leave the invoice line item field Tax Provider empty. On completion, JustOn sets the value Internal to indicate the origin of the tax calculation on the invoice line item.

Fix Tax Rate

If you sell products that always have the same tax rate, the invoice line item needs the following field to be set for the internal tax calculation to work:

Field Data Type Description Example Value
Product Tax Rate Percent (3,3) Specifies the actual tax rate. 19%

There are several ways to set the value for the Product Tax Rate field:

  • Using data mappings, retrieving the value from virtually any field of any object,
  • Using the ON field mechanism, retrieving the value from a custom field ON_ProductTaxRate of any source object or (for compatibility reasons with older JustOn versions) from the custom field ON_TaxRate of a price book entry,
  • Via a data import.

Variable or Multiple Tax Rates

If you sell products with different tax rates or operate different markets where variable or multiple tax rates apply, you need rules to determine the correct tax rate for an invoice line item. To this end, JustOn supports tax rules. They provide for tax rate lookups along various combinations of account region, merchant or tenant region, product tax class, etc.

To have JustOn calculate the taxes based on tax rules, you set up the tax rules that meet your business requirements. For details about understanding and configuring tax rules, see Tax Rules.

Precalculated Tax

Certain business use cases require to pass through taxes that were precalculated by an external system, like a web shop or an ERP system. When doing so, you turn off JustOn's internal tax calculation.


The precalculated tax support is available as of JustOn 2.46.

For JustOn to deal with precalculated taxes, the invoice line item needs the following fields to be set:

Field Data Type Description Value
Tax Provider Picklist Specifies the provider that calculates the tax detail.
Precalculated disables the tax calculation.
Tax Rate Percent (3,3) Specifies the tax rate that applies to this invoice line item. With precalculated taxes, this value is passed through for display purposes, but it is not used for calculation. percentage tax rate to be displayed for the invoice line item
Precalculated Tax Currency (16,2) Specifies the absolute tax amount as calculated by a third-party system. precalculated tax amount

There are several ways to set the values for the Tax Rate and Precalculated Tax fields:

  • Using data mappings, retrieving the values from virtually any fields of any objects,
  • Using the ON field mechanism, retrieving the values from custom fields ON_TaxProvider, ON_TaxRate and ON_PrecalculatedTax of any source object,
  • Via a data import.

External Tax Provider

Some countries, like the United States or Canada, have very complex sales tax rules that are difficult to manage. To facilitate corresponding business use cases, JustOn allows for retrieving tax data from an external tax provider.


The tax data retrieval is available as of JustOn 2.43.

Currently, JustOn supports the AvaTax service from Avalara as external tax provider.

For more details about tax data retrieval and the AvaTax integration, see Setting Up Tax Data Retrieval and Setting Up Tax Data Retrieval From AvaTax.