[vacooom]

I don't have a good resource that summarizes the various rules, but high-level this is the mechanism:

For B2B: 1. If the seller is extra-EU, and the buyer in EU, no VAT is charged 2. If the seller is in one EU country, and the buyer is in a different EU country, no VAT is charged by the seller, but the buyer has to do a "VAT reverse charge" (it still nets to 0€ paid, but there is extra paperwork involved) 3. If the seller and the buyer are in the same EU country, they charge the regular VAT rate

For B2C things are a lot more complicated for cross-border transactions, and there is a difference between selling goods and services. For digital goods, as a seller, you would need to charge the VAT of the country of the _buyer_, and gather two pieces of evidence about the country the buyer resides in, then remit the taxes through the VAT MOSS system. Not fun. That's why Paddle & co are popular.