How much of decentralization is there on a DEX?

  1. A website of a DEX is hosted and run as a normal centralized one, correct? Via ordinary DNS, that is, with an ordinary centralized hosting provider.

  2. What does then the notion of “decentralized exchanged” refer to? Is it only to the fact action of exchanging coins is executed without a third party?

That doesn’t have to be the case. The DEX can be hosted on IPFS ( and I think Arweave can host websites, too ), which are both decentralized storage solutions. Arweave has the advantage that the hosting is permanent, while IPFS isn’t permanent if there is no longer anybody choosing to host them. Both allow you to verify that the content delivered is unmodified, even if you get it from an untrusted party, though.

As for DNS, you can use decentralized DNS, too. There are such a thing as .eth domains, which are hosted on Ethereum, and other domain extensions provided by Unstoppable Domains, such as .crypt, .wallet, and others.

Obviously not all DEXs will be hosted this way, but they could be. I know that at least Tornado Cash ( which isn’t necessarily a DEX, but still ) has an Ethereum domain: https://tornadocash.eth.link/.

I think that is primarily what people think of when they refer to a decentralized exchange. In fact an article argued that, from a certain perspective, there’s “no such thing” as a decentralized exchange, as a thing. You can only make a decentralized exchange as an action.

I’d say that practically it’s useful to use the term decentralized exchange to describe a platform created by somebody to help you make decentralized exchanges, but author still has a certain point.

The point of decentralized exchange websites is that the author of the website doesn’t hold your money , or anybody else’s, while doing exchanges. This is important legally, and for security and not having to trust a 3rd party. As long as you trust the smart contract, you don’t have to trust anybody else. You are in charge of what happens to your money. Nobody else can spend it or prevent you from spending it, unless of course that’s exactly what you trusted the smart contract to do for you.