Brink

"The State Of Bitcoin Core" by @bitschmidty of @bitcoinbrink "There's a paradox in Bitcoin Core in that... the code is transparent, but understanding of the code is scattered in IRC and other places" 100 slides on the who & what of the @bitcoincoreorg project.

“Im looking forward to continuing to support current and upcoming privacy proposals with a strong focus on code review in general and occasional unexpected side journeys such as implementing the first SwiftSync PoC. Thanks to Brink for supporting me throughout this journey” 🧡

Sebastian’s next priorities are getting silent payments merged into libsecp256k1, activating the DLEQ module, reviewing BIP54 (the Consensus Cleanup), working on FROST threshold signatures and helping with the ongoing effort to remove libevent as a Bitcoin Core dependency.

This month, we're celebrating five years of Sebastian Falbesoner (@theStack) working on Bitcoin Core and libsecp256k1 at Brink. Sebastian started with often unglamorous test work, steadily widening his scope, and eventually stepping up to steward impactful privacy proposals…

Stéphan Vuylsteke (@stphnvlstk) joined Brink in 2022 and works full time on Bitcoin Core development. In 2025, he deepened his involvement with the Bitcoin Kernel project, the effort to extract Bitcoin Core's consensus logic into a standalone, reusable library…

Hennadii Stepanov (@hhebasto) has been contributing to Bitcoin Core since 2018 and became the project's GUI maintainer in 2021. In 2025, he left over 1,800 review comments and continued his extraordinarily wide-ranging work across the build system, platform support, GUI, translations, CI infrastructure, and libsecp256k1…

How can we automatically test Bitcoin nodes with millions of different tests/day without changes to the software itself while considering non-deterministic factors like time &randomness? Niklas Gögge (@dergoegge) explores in part 2 of our Fuzzamoto series brink.dev/blog/2026/04/0…

Eugene Siegel joined Brink as a grantee in April 2025, bringing experience in Bitcoin Core's P2P and networking code. His grant focuses on fuzz testing, particularly improving coverage of Bitcoin Core's most security-sensitive message processing and validation code...

Fabian Jahr (@fjahr) established himself as someone who can drive complex, multi-year projects across both Bitcoin Core and libsecp256k1, from the practical (getting AssumeUTXO deployed to mainnet, ASMap) to the research-oriented (advancing cross-input signature aggregation)…

Niklas Gögge (@dergoegge) has built a reputation as one of Bitcoin's most effective security engineers by finding vulnerabilities through testing, responsibly disclosing them, and then building infrastructure so that similar bugs can be caught automatically in the future...

Michael Ford (@fanquake) has been a Bitcoin Core contributor since 2012 and maintainer since 2019. He is often the first to comment on a new pull request and colleagues have praised his encyclopedic knowledge of everything happening across the codebase…

Brink has been funding Sebastian Falbesoner (@theStack) since 2021, initially for part-time review-focused work. In 2025, he upgraded to full-time, a transition that has proven to be enormously productive...

Marco De Leon (@macrohead7) completed his transition from Brink fellow to full-time grantee, establishing himself as a capable contributor across multiple areas of the codebase. He drove the txid type safety project to completion across six pull requests, successfully removed Bitcoin Core's legacy checkpoints, left nearly 250 review comments, and contributed to fuzz testing infrastructure and P2P code review.

None of this work would be possible without the generosity of Bitcoiners who share our mission of strengthening Bitcoin by ensuring that Bitcoin's codebase continues to be maintained, tested, reviewed, and improved in a “Move slow, fix things” fashion. Thank you.

For those wanting an even deeper look, we have compiled companion reports for each engineer: - A markdown file explaining all authored PRs - A CSV containing each authored PR - A CSV linking to each PR reviewed

Today we’re publishing Brink's 2025 Engineering Impact Report covering the work of the eight Bitcoin Core engineers we funded last year and why we think this work is important.