A decentralized platform (dApps) can't sell crypto for fiat on its own, because smart contracts can't directly deal with assets in the 'real world'. However, decentralized services can partner up with official crypto processing providers, such as CoinsPaid
, to accept crypto payments or offer a fiat gateway.
Another type of service in the decentralized category is a P2P exchanger. It's a sort of marketplace where individual Bitcoin sellers and buyers meet. Every seller can set their own terms, exchange rate, and payment options, though most accept credit cards. The most popular site of this type is LocalBitcoins. You can buy up to $1000 worth of BTC without full verification, though you'll still need to provide your full name, country, and email.