Fluidkey

Fluidkey uses stealth addresses to keep incoming payments from being traced, following ERC-5564. A signing wallet derives a spending key and a viewing key; the spending key stays local while a child node of the viewing key goes to the server, which watches the chain and generates addresses. A payer only enters a fixed name, and the resolver returns a one-time address on the spot, so the ledger records only transfers that appear unrelated.

Each stealth address is a 1/1 Safe smart account deployed counterfactually: no contract is created when funds arrive, and only when the user spends does a relayer deploy the account and cover gas, with the fee taken from the stablecoin balance. That avoids funding a transfer from a public address and creating a link. The viewing key rotates monthly, so access can be opened to an accountant or auditor for a chosen period, and a separate recovery interface can replay the derivation sequence to recover addresses even if the service stops.