Tax

Overview

Smartstore abstracts tax calculation into two parts: a provider resolves the tax rate and a calculator applies that rate to prices. Everything is driven by TaxSettings which determine whether amounts are entered and displayed inclusive or exclusive of tax.

Tax categories

Every product is assigned to a tax category so the system knows which rate to apply. Categories are simple records with a name and display order and can be edited in the admin area under Configuration → Taxes.

Tax providers

The active provider is selected via ITaxService and returns a TaxRate for a given TaxRateRequest. Smartstore ships with a fixed rate provider and a region‑based provider in the Smartstore.Tax module, but you can implement your own by registering an ITaxProvider.

public class CustomTaxProvider : ITaxProvider
{
    public Task<TaxRate> GetTaxRateAsync(TaxRateRequest request)
    {
        // return 7% for books, otherwise 19%
        var rate = request.TaxCategoryId == 5 ? 7m : 19m;
        return Task.FromResult(new TaxRate(rate, request.TaxCategoryId));
    }
}

Calculating tax

ITaxCalculator exposes helpers for products, checkout attributes, shipping and payment fees. The calculator looks up the applicable rate, applies rounding and returns a Tax structure containing both net and gross values.

public async Task<Money> GetGrossPriceAsync(Product product, decimal netPrice)
{
    var tax = await _taxCalculator.CalculateProductTaxAsync(product, netPrice, inclusive: true);
    return _taxService.ApplyTaxFormat(tax.Price);
}

Display and formatting

To append legal suffixes such as “incl. VAT” use ITaxService.ApplyTaxFormat and its shipping/payment variants. Suffix visibility and whether prices include tax are governed by TaxSettings.DisplayTaxSuffix and TaxSettings.PricesIncludeTax and must be passed to the method ITaxService.ApplyTaxFormat to take effect.

VAT numbers and exemptions

ITaxService also validates EU VAT numbers and checks whether a product or customer is tax exempt:

var vat = await _taxService.GetVatNumberStatusAsync("DE123456789");
bool exempt = await _taxService.IsVatExemptAsync(customer);

Tax settings

Injecting TaxSettings gives access to configuration such as the default tax address, whether shipping or payment fees are taxable and which provider is active.