Peter Todd, a longtime Bitcoin Core contributor, has joined the MARA Foundation as lead maintainer of Slipstream, the organization's private Bitcoin mempool service. The appointment was announced on October 1, 2026.

Slipstream enables users to submit Bitcoin transactions directly to MARA Pool, the company's mining pool, without routing them through Bitcoin's public peer-to-peer network. Transactions remain private until they are confirmed in a block. The service supports non-standard or large transactions that may not propagate easily under standard relay policies.

Role and Background

Todd will be responsible for developing and operating the service. He is known for co-authoring BIP 125, which formalized opt-in replace-by-fee, creating OpenTimestamps, and launching Libre Relay in 2024. Libre Relay is a Bitcoin Core fork that applies more permissive relay rules for certain non-standard transactions.

Todd has long argued that mempool policy should align with economic demand from miners rather than impose restrictions that limit how Bitcoin can be used. He has described the Slipstream role as a natural extension of his work on Libre Relay and broader mempool policy.

He also noted that the position offers a chance to connect Bitcoin Core developers more closely with miners.

Recent Applications of Slipstream

Slipstream first attracted attention in 2024 for handling large Ordinals inscriptions. More recently it has supported research projects, including work on quantum-safe Bitcoin transactions and Binohash, a method for emulating covenants without a soft fork.

The service proved useful during the July 2026 Coldcard firmware vulnerability. The flaw affected firmware versions from 2021 through July 2026 and involved weak entropy generation. Some multisig users relied on Slipstream to move funds while limiting public exposure of key material before confirmation. MARA Foundation reported that more than 10,000 Bitcoin has been transferred from affected wallets through the service.

Because submissions do not enter the public mempool until mined, the approach reduces the window in which an attacker could observe and attempt to front-run a recovery transaction. The protection is most relevant when addresses have not previously been reused.

Technical Context

Bitcoin's relay policy consists of local rules that nodes apply to unconfirmed transactions before accepting them into their mempools. These rules are separate from consensus. A valid transaction can still be rejected by nodes that decline to relay large or non-standard formats.

Slipstream bypasses that path by submitting directly to MARA Pool, provided the transaction meets protocol rules and pays a sufficient fee. The service remains subject to MARA's terms of service and applicable law.

Todd is expected to continue using Slipstream for experimental development while maintaining its operational role in handling specialized transaction flows.