Bitcoin Protocol
Bitcoin Protocol Layer 1 Masterclass 01 / 08

Jon Atack

Bitcoin Core Contributor • BIPs Editor • Open Source Developer

Biography

Jon Atack is one of the most active and respected Bitcoin Core contributors in the world. A software engineer with decades of experience, he pivoted to full-time Bitcoin development in 2019 and quickly became one of the top code reviewers and contributors to the project.

Before Bitcoin, Jon built a distinguished career in open-source software. He was the maintainer of Ransack, a Ruby search library that has been downloaded over 103 million times, making it one of the most popular Ruby gems in history. He studied engineering at Harvey Mudd College and earned an MBA from INSEAD.

Jon participated in the Chaincode Labs residency program, which deepened his Bitcoin protocol expertise. He is currently based in El Salvador, one of the first countries to adopt Bitcoin as legal tender.

His work has been funded by major Bitcoin grants from Spiral (Block), OpenSats, and Maelstrom (Arthur Hayes), reflecting the community's confidence in his contributions to Bitcoin's foundational layer.

Technical Contributions

Jon's contributions to Bitcoin Core span multiple critical areas of the codebase:

  • Peer-to-Peer Networking: Major work on Bitcoin's P2P layer, including I2P integration (SAM v3.1 support) and CJDNS network support, enhancing Bitcoin's network privacy and resilience against surveillance.
  • BIPs Editor: Appointed as a Bitcoin Improvement Proposals editor in April 2024, joining the small group responsible for reviewing and managing the formal specification process for Bitcoin protocol changes.
  • Code Review: One of the most prolific code reviewers in Bitcoin Core history. His review philosophy emphasizes thoroughness and he has authored comprehensive guides on how to review Bitcoin Core PRs.
  • AddrMan & Peer Management: Significant contributions to Bitcoin's address manager and peer connection logic, improving how nodes discover and connect to each other.
  • Test Coverage: Extensive work on improving Bitcoin Core's test suite, particularly for P2P and RPC functionality.

Masterclass: Bitcoin Protocol

This foundational masterclass covers Bitcoin's base layer — the consensus protocol that everything else is built upon. Jon brings the perspective of someone who works directly in the Bitcoin Core codebase every day.

Bitcoin Protocol Deep Dive
Layer 1 • Feb 24, 2026

Topics likely covered include:

  • Bitcoin Core architecture and the development process
  • Peer-to-peer networking: how nodes discover, connect, and share data
  • Consensus rules and validation logic
  • The BIP process: how Bitcoin evolves
  • Privacy at the network layer: I2P, CJDNS, Tor integration
  • Code review methodology for safety-critical software

Resources & Preparation

Bitcoin Development Resources
Jon's curated repository of resources for contributing to Bitcoin Core.
How to Review Bitcoin Core PRs
Comprehensive guide to reviewing pull requests in the Bitcoin Core project.
How to Contribute PRs to Bitcoin Core
Step-by-step guide for making your first contribution to Bitcoin Core.
Bitcoin Core Repository
The main Bitcoin Core codebase. Browse Jon's commits and reviews.
Bitcoin Improvement Proposals
The BIPs repository where Bitcoin protocol changes are formally specified.
Bitcoin Core PR Review Club
Weekly review sessions for learning how to review Bitcoin Core code.