Maelstrom, the family office of BitMEX co-founder Arthur Hayes, published its first annual report for its Bitcoin Grant Program, documenting achievements across a 20-month initiative that began in October 2024. The report reveals four active developers—Rkrux, Stratospher, Benalleng, and Macgyver—have advanced Bitcoin's privacy, security, and codebase resilience, with five developers supported in total since inception. Grant Program Administrator Jonathan Bier authored the report, which details technical output across Bitcoin Core development and privacy infrastructure. Grants are issued on 12-month contracts, paid monthly in Bitcoin, with a cap of $400,000 per developer per year, funded wholly by Maelstrom.
Rkrux and Stratospher Advance Bitcoin Core Development
Two grantees focused on Bitcoin Core, the software running nodes that secure the Bitcoin network. Rkrux, a grantee since October 2024, made 1,155 review comments across more than 200 pull requests in 2025, ranking him the 11th most active commenter on the entire codebase according to a dashboard built by developer Niklas Gögge cited in the report. In the first five months of 2026 he added more than 400 additional pull request comments. His work spans MuSig2—a protocol making multisignature transactions indistinguishable from single-signature transactions on-chain—and the deprecation of legacy wallets in favor of descriptor-based wallets.
Stratospher, a grantee since November 2025, concentrated on consensus-critical validation code and the peer-to-peer network. She discovered and fixed an undefined behavior bug in Bitcoin Core's FindMostWorkChain function, contributed to the removal of the BLOCK_FAILED_CHILD flag, and worked on DLEQ cryptographic proofs in libsecp256k1 related to Silent Payments. She presented at the Africa Bitcoin Conference on two panels covering open source development and privacy.
Benalleng and Macgyver Build Privacy Infrastructure
Benalleng, funded since June 2025, works full time on Payjoin—a transaction protocol allowing both sender and receiver to contribute inputs to a Bitcoin transaction. The Payjoin API has been integrated into Bull Bitcoin and Cake Wallet, with five or more additional wallet integrations currently in progress per the report. Bindings for Python, Javascript, Dart, and CSharp have been released.
Macgyver, also funded since June 2025, focuses on Silent Payments—a protocol proposed by Ruben Somsen in 2022 that allows senders to make multiple payments to a recipient using a single static address without reusing that address on-chain. Blindbit-Desktop, Cake Wallet, and Dana Wallet now support both send and receive phases, while Sparrow Wallet and Nunchuk have added send support. Bitcoin Core has draft implementations for both phases but they remain on hold pending a dependency on the Silent Payments module in libsecp256k1 per the report. Macgyver formalized the Silent Payments roadmap, produced BIP-375 test vectors, proposed the first working BIP-375 hardware signer implementation for Coldcard, and organized monthly Silent Payments working group meetups.
Maelstrom Structures Grants as 12-Month Bitcoin-Paid Contracts
The grant framework funds open-source Bitcoin protocol work only, with no commercial strings attached and no token incentives involved. The review committee consists of two people: Arthur Hayes and Jonathan Bier. Grants are issued on 12-month contracts, paid monthly in Bitcoin, and can be stacked up to a cap of $400,000 per developer per year. The program is wholly funded by Maelstrom per the report.
FAQ
How long has Maelstrom's Bitcoin Grant Program been running?
The program began in October 2024 and has been running for 20 months as documented in the first annual report.
Which developers are currently active in the program?
Four developers are currently active: Rkrux and Stratospher working on Bitcoin Core, and Benalleng and Macgyver working on privacy infrastructure. Five developers have been supported in total since inception.
What is the funding structure for Maelstrom's Bitcoin grants?
Grants are issued on 12-month contracts, paid monthly in Bitcoin, with a cap of $400,000 per developer per year. The program is wholly funded by Maelstrom, the family office of BitMEX co-founder Arthur Hayes.
