Google engineer who became an early Bitcoin contributor and corresponded with Satoshi
On April 12, 2009, a Google engineer named Mike Hearn read the Bitcoin whitepaper and emailed Satoshi Nakamoto. Over the next two years they exchanged sustained technical correspondence — scaling, simplified payment verification, the long-run shape of mining. Hearn received one of the last private emails Satoshi ever sent, coming almost exactly two months after Satoshi’s last known email in the Malmi archive — itself a reply to Gavin Andresen, with Malmi only copied and mentioned in the third person:
I’ve moved on to other things. It’s in good hands with Gavin and everyone.
Three days later, Satoshi sent Andresen the alert-key handover that is generally reckoned his absolute final email; the Hearn and Andresen messages are treated as a single two-part farewell in the account of that closing correspondence.
Almost five years later, on January 14, 2016, Hearn published “The resolution of the Bitcoin experiment” on Medium. After recalling that he had always called Bitcoin an experiment that could fail, he wrote:
But despite knowing that Bitcoin could fail all along, the now inescapable conclusion that it has failed still saddens me greatly.
He sold all his bitcoins, left the project, and joined R3, an enterprise-blockchain consortium where he co-led development of the Corda distributed ledger. His departure closes Phase 1 of the block-size war, which opens with the Bitcoin XT fork he championed as a Large-blocker faction lead.
In August 2017 he made his Satoshi correspondence public — one of the largest documented bodies of Satoshi’s technical thinking.
In February 2024 he testified in the COPA v Wright trial. In a 2025 CoinGeek interview, Hearn offered rare reflections on Satoshi’s personality, describing him as open to experimentation and, in Hearn’s reading, ultimately driven away by the zealotry of his own community.
Hearn worked at Google on Maps, Earth, and Gmail’s anti-spam systems. He developed BitcoinJ, a Java implementation of the protocol — the first major alternative to the original C++ client and the basis for many Android Bitcoin wallets.
Between April 2009 and April 2011, Hearn and Satoshi exchanged sustained technical email. Topics included how the system could scale, how simplified payment verification (SPV) clients would work, and how Satoshi envisioned the evolution of mining from CPUs to specialized hardware. Hearn was among the very first people outside the initial cypherpunk circle to take a serious technical interest in Bitcoin, and the published archive of his correspondence with Satoshi documents the technical thinking Satoshi never spelled out in public posts. When Hearn asked in January 2011 for the working behind the 21 million cap, Satoshi’s answer named the range he wanted ordinary amounts to fall in, “from 0.01 to 1000”; that range is followed through the code and the record in the analysis titled “Satoshi counted in cents.”
The January 2016 departure essay cited two principal grievances: the inability of the development community to reach consensus on raising the 1-megabyte block size limit, and what Hearn described as systemically important institutions emerging within what was supposed to be a decentralised system. He sold his coins concurrent with publication.
53 entries / 5 threads
Satoshi's code had a COIN and a CENT and nothing smaller with a name. Bitcoin's smallest unit, the satoshi, was named by users on BitcoinTalk two months after his last post.
Mike Hearn notes that Satoshi never thought the decimal point through and is now absent, and proposes letting miners vote on where it should go.
Satoshi sized the 21 million cap so amounts would land between 0.01 and 1000. The cent ran through his code, his fees and more than two years of his writing. The yen does not appear even once.
Doubters called it unscalable in 2008. A famed hacker failed to break the code. A judge, a dictionary, and a Nobel nominator weighed in. What others said about Satoshi, read as one record.
Weighing the 'Blockstream controls Bitcoin' charge against the documentary record: where it comes from, and how each link in the chain holds up.
When correspondents wished Satoshi merry Christmas, predicted $10M per coin, or hoped he was well, his replies went straight to the technical point and ignored the rest. Five patterns, examined.
Bitcoin's 2015–2017 block-size war by phase, faction and turning point: Bitcoin XT, the BIP148 UASF, the New York Agreement, Bitcoin Cash and the cancellation of SegWit2x.
Satoshi grants Malmi developer access on SourceForge, agrees on a password-protected wallet feature, and shares a long Q&A dump of frequently-asked Bitcoin questions for the planned FAQ.
Why Bitcoin's 2015-2017 fork wars were fights over what Bitcoin is, not OSS disputes: the authority vacuum after 2011, the money riding on rule choices, and three layers binding code to currency.
Mike Hearn and Gavin Andresen released Bitcoin XT 0.11A, a Bitcoin Core fork implementing BIP 101 — 8 MB blocks doubling every two years. The launch opened the public phase of the block-size war.
Genealogy of every Bitcoin protocol fork that left a separate chain alive (Bitcoin Cash, SV, Gold) and the adjacent cryptocurrencies derived from Bitcoin (Namecoin, Litecoin, Dogecoin).
How the 2014 'Bitcoin Core' rebrand changed the language of authority in Bitcoin: the internal disagreement over PR #3408, the 2015-2017 forks, and Hearn's regret in 2025.
The Mixmaster developer who died 68 days after Satoshi's last known email. The evidence for Len Sassaman as Satoshi, weighed.
Jameson Lopp argues Hal Finney could not have been Satoshi: on April 18, 2009, Finney was running a 10-mile race in Santa Barbara during a window of Satoshi network activity.
Mike Hearn published The Resolution of the Bitcoin Experiment, declaring Bitcoin had failed due to governance breakdown and the block-size stalemate. He sold all his coins and left the project.
Mike Hearn testifies at the COPA v Wright trial, recounting his direct interactions with Satoshi and describing how Wright failed his technical check questions at a 2016 dinner.
In a CoinGeek interview, Mike Hearn offers rare reflections on Satoshi's personality — observing he enjoyed experimenting but appeared to grow frustrated when evangelical personalities arrived.
Mike Hearn announces the open-source release of BitcoinJ under the Apache 2 license, and asks about merkle branch verification, scripting language ideas, and why transaction replacement was disabled.
Mike Hearn describes his work on Google's abuse team and proposes using Bitcoin as collateral against accounts for spam prevention, asking about time-locking coins.
Mike Hearn asks Satoshi whether the Electronic Funds Transfer Act could apply to Bitcoin and if the inability to do chargebacks risks making it illegal.
Mike Hearn asks about the origin of the 21 million coin limit, the 10-minute block target, and the 500KB block size limit while working on a Java SPV implementation for Android.
Mike Hearn contacts Satoshi Nakamoto for the first time with questions about Bitcoin's scalability, mining hardware, inflation schedule, and coin denominations.
Mike Hearn's private email correspondence with Satoshi Nakamoto, in which Satoshi stated he had 'moved on to other things' and that Bitcoin was 'in good hands with Gavin and everyone.'
Satoshi's final known private messages: April 23, 2011 to Mike Hearn — "in good hands with Gavin." April 26 to Andresen, transferring the alert key and saying he would probably be unavailable.
Mike Hearn publishes his private email correspondence with Satoshi Nakamoto, providing valuable insights into Satoshi's thinking about Bitcoin's technical future.