# Sales tax overview
When it comes to taxes, Orderwave has flexible options for connecting to tax rate providers, or allowing you to create your own tax optimizations using Rules.
By default, Orderwave provides a tax-rate lookup service called Knox. Knox is a basic service that looks up tax-rates in the US by zip code. This is primarily used for orders placed directly in Orderwave, though it can be used to lookup new rates on an existing order if the shipping address is changed by a user.
Knox refreshes its tax rates on a monthly basis and provides and accurate and adequate level of detail for most online businesses. However, if you require more complex tax look-ups and functionality, such as nexus/remittance, you can consider using other tax providers.
# Configuring tax look-ups
Orderwave will only look up tax rates for orders that are tagged with the tag Tax-Lookup. Tax-Lookup is a built-in tag with Orderwave that indicates that the order should have taxes loaded via a lookup service (not just Knox).
Orderwave comes with a rule that automatically tags orders that do not have order-numbers with the Tax-Lookup tag. This is because orders that do not have order-numbers are placed directly in Orderwave, and they likely need to have their tax rates fetched. The rule is called TAX-TAG, and you can customize its matching properties to meet your business needs.
Orderwave comes with another rule, named KNOX-TAX-LOOKUP that performs the tax look-up using Knox whenever an order is created. If you implement a different process/provider for tax rate look-ups, you will need to disable this rule, and create another one, to pull the Knox look-ups out of the process.