Bisq is a decentralized, peer-to-peer exchange for buying and selling bitcoin with national currencies or other cryptocurrencies. No account creation, no KYC, no central server — trades are coordinated over Tor and settled via 2-of-2 multisig escrow with a third-party mediator.
HodlHodl is a non-custodial, peer-to-peer bitcoin exchange platform. Unlike Bisq, it is web-hosted rather than fully decentralized, but it remains non-custodial through 2-of-3 multisig escrow.
Comparison of peer-to-peer Bitcoin exchanges: Bisq, RoboSats, HodlHodl, LocalBitcoins (deprecated), and emerging decentralized order books.