Paul on Nostr: Potentially yes, you would have to collect VAT. Unfortunately it's a mess of some ...

Potentially yes, you would have to collect VAT. Unfortunately it's a mess of some things done per-country and some things are EU standardised.

It will be a *lot* easier for you if the conference charges the fee as part of registration and then you charge them for the total (but won't solve all the issues).

The thresholds for VAT are very low in the EU, usually low thousands to low tens of thousands of euros (not millions). In some cases there's no minimum.