Package relay

Package relay is a proposed Bitcoin relay feature that lets nodes accept or reject a group of related transactions as one package. Instead of looking at each transaction in isolation, the node evaluates the combined feerate and relationships across the whole set.

This matters because some useful fee-bumping patterns depend on a low-fee parent and a higher-fee child. Without package relay, a node may reject the parent before it ever considers the child, which breaks Child Pays for Parent (CPFP) in cases where the parent fee is too low for current mempool conditions.

That limitation matters most for time-sensitive protocols. Lightning channels, vaults, and other contract systems may need to attach fees after the fact in order to confirm before a timeout. Package relay aims to make those fee-bumping strategies more reliable without weakening denial-of-service protections on the peer-to-peer network.

BIP 331 specifies ancestor package relay for Bitcoin's peer services layer. As of mid-2026, the proposal remains under active design and implementation review.

References

• Bitcoin Optech: Package relay
• BIP 331: Ancestor Package Relay