I have a site which will use Umbraco Commerce. There are special VAT rules and ideally we would be able to calculate the VAT outside of Umbraco Commerce. Is it possible to do this and then just update Umbraco Commerce with the relevant amount of VAT? The same goes for shipping, can we work out the cost of shipping separately and update Umbraco Commerce with the correct amount?

@CodeSharePaul when I ran into this on the US side. What I ended up doing was basically using a Vendr "Price Adjustment" to apply the custom calculated shipping or tax (VAT in your case i think). For the tax we used a third party service, fetched the rate and then stuffed the order as needed. I'm not sure if this is a help as its quite old now: https://our.umbraco.com/packages/website-utilities/vendr/vendr-support/107825-calculate-shipping-in-cart-with-custom-shipping-calculator

@TECKSPEED thank you mate

@CodeSharePaul sure thing, I am not sure how Umbraco Commerce has changed, if at all, but generally everything was a "price adjustment" before finalizing the order. Once the order was finalized we considered it "set in stone"