Peter Todd, a long-time Bitcoin Core contributor, has become the head maintainer of Slipstream, a service operated by MARA Foundation that directs transactions to MARA Pool without routing them through Bitcoin's public peer-to-peer network.
Todd's background in transaction relay and fee policy positions him for the role, particularly given Slipstream's design for transactions that may face difficulties moving through standard mempools. Todd co-authored BIP 125, which standardized opt-in replace-by-fee, and previously created Libre Relay, a modified version of Bitcoin Core with relaxed relay rules.
Private Mempools and Transaction Privacy
Todd announced his involvement with Slipstream and connected it to the broader issue of private transaction channels. He noted plans to discuss private mempools at TABConf and referenced the Coldcard security incident as a practical application of the service.
Bitcoin's relay policy operates separately from its consensus rules. Relay policy consists of additional, locally configurable rules that nodes apply to unconfirmed transactions before adding them to their mempools. These rules no longer apply once a transaction is included in a block.
Slipstream's Role in Recovery and Experimentation
MARA introduced Slipstream in February 2024 to process large and non-standard transactions. The service allows users to bypass standard relay procedures by submitting transactions directly to MARA Pool, which enforces Bitcoin's consensus and fee requirements.
During the Coldcard firmware vulnerability disclosed in July 2026, Todd highlighted Slipstream's utility for recovery transactions. Users with affected wallets faced a risk that recovery transactions exposing multisig scripts could remain unconfirmed long enough for attackers to create competing transactions with higher fees. By keeping transactions private until they reached a block, Slipstream reduced this exposure risk.
MARA Foundation reported that Slipstream facilitated the transfer of over 9,000 BTC from affected multisignature wallets. The service has also enabled experimental transactions, including StarkWare's quantum-safe Bitcoin transaction, which reached mainnet through Slipstream after failing to proceed through the standard mempool.
Implications for Bitcoin Transaction Routing
Private channels like Slipstream offer miners an alternative path for processing transactions that public relay rules might reject, whether during security emergencies or experimental deployments. However, these services operate outside the public mempool, raising questions about how private transaction routing will evolve as miners expand their role in transaction processing.
