Private Transaction Relay

A private transaction relay is a service that accepts your signed transaction and passes it directly to block builders or validators rather than broadcasting it to the public mempool, so it is not visible to searchers while it waits to be included. The purpose is protection from the attacks that read pending transactions: a large swap sitting in the open mempool with a loose slippage tolerance is an invitation to be sandwiched, and a liquidation or an arbitrage that anyone can see is an invitation to be front-run. Routing through a relay removes the window in which that is possible, and several relays additionally return a share of any extractable value back to the sender rather than letting it accrue to the searcher. The trade-offs are real and worth stating. You are trusting the relay operator not to look at, delay, or act on your order flow — privacy from the public mempool is not privacy from the relay. Inclusion can be slower or occasionally fail, because you are relying on a subset of builders rather than the whole network. And nothing about it is private once the block is published: the transaction lands on chain in full view, so a relay protects the moments before confirmation, not the record afterwards. Most wallets now offer this as a toggle or an alternative RPC endpoint; it is worth switching on for large or mechanical trades, and it is not a substitute for setting a sane slippage limit.