# Customer codes

Source: https://developer.avalara.com/avatax-dm-combined-erp/sales-tax-badge/transactions/simple-transactions/customer-codes/

# Customer codes

The `customerCode` value identifies the customer who is transacting with the company. Because a transaction is legally defined as a transaction between a buyer and a seller, the `customerCode` and `companyCode` values identify the two parties involved in the transaction.

For example, if the transaction type is a `SalesInvoice`, the transaction is deemed to be a sale made by the company identified by `companyCode` sold to the buyer identified by the `customerCode`.

This determination is necessary in order for our software to correctly handle exemption certificates. In AvaTax, the `customerCode` is used to identify customers who have exemption in either AvaTax or in CertCapture. So AvaTax requires a `customerCode` field to ensure that exemptions will work correctly when you begin working with certificates.

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