Braiins Pool.

In November 2010 Marek Palatinus, known online as slush, had been mining bitcoin in Prague for a few weeks, on three ordinary processors, without finding a single block. Since people had started mining with graphics cards, he wrote on the Bitcoin forum, now BitcointalkBitcointalkThe Bitcoin forum Satoshi Nakamoto opened in November 2009. Much of Bitcoin’s early history, from the pizza offer to Satoshi’s last post, happened there., “mining became very hard for other people”. His answer was a mining poolMining poolA group of miners who share the work of finding blocks and split the rewards, so each gets paid steadily instead of rarely.: “Join poor CPU miners to one cluster and increase their chance to find a block!” Each member’s computer would send in shares, small proofs of the work it had done, and whenever one of them found a block, the reward would be split by shares. He opened the pool on 16 December 2010, and that morning it found its first block, 97,834.

Braiins, the Prague company that runs it now, calls it the world’s first publicly available pool. But another programmer, Chris Double, had opened one that found a block on 4 December and closed it on 17 December, after so many miners left that a block would take too long; his page about it calls Palatinus’s “the second public bitcoin pool to start operating”.

Palatinus’s pool lasted, though running it alone grew hard. “I did not imagine there will be so large demand few hours after going live,” he had written on its first day. In March 2012 thieves broke into a server it rented and took 3,094 bitcoins waiting to be paid out, a loss he covered from his own money. In 2013 Braiins, founded by Jan Čapek and Pavel Moravec, took over the running of the pool and a majority stake, leaving him free to build the Trezor hardware walletHardware walletA small device that holds your private keys and signs payments inside itself, so the keys never touch your internet-connected computer or phone.. First called Bitcoin.cz Mining Pool, it became Slush Pool in 2016, after the name many people already used, and Braiins Pool in 2022, two years after Braiins bought Palatinus’s remaining share. Braiins says it has mined more than 1.3 million bitcoins since 2010.

Along the way the pool shaped who decides what goes into Bitcoin’s blocks. In 2012 Palatinus designed StratumStratumThe protocol most mining pools use to hand out work to miners’ machines and collect the results. Marek Palatinus introduced it in 2012., a common language in which a pool hands out work to its miners’ machines, which Braiins says has been “the standard protocol for pooled mining” ever since; its “one significant downside”, in Braiins’s words, was that miners could no longer choose the transactions in their blocks. In August 2015, in the argument over bigger blocks, the pool was the only large one whose blocks backed Bitcoin XT, a version of Bitcoin’s software from Mike Hearn and Gavin Andresen that would have raised the limit on block size, and it left that choice to each miner: about 10% of its mining power chose to, Bitcoin Magazine reported. In 2019 Braiins and the developer Matt Corallo published Stratum V2, designed partly to give miners that choice of transactions back.

For 13 years the pool paid its miners only from the blocks it found, using a scoring method, first used by Palatinus, that was designed to stop miners profiting by hopping from pool to pool. On 12 December 2023 it switched to full pay per share, or FPPS: a set amount for every share, whether or not the pool finds a block. Each Braiins Pool block’s first transaction pays the whole reward to the pool’s own address, and the pool pays its miners separately, on chain or, since February 2024, over the Lightning NetworkLightning NetworkA network built on Bitcoin for payments through channels, without recording every payment as its own blockchain transaction.. These are payments to the pool’s miners, separate from the transactions confirmed inside the block.

Researchers have found that in the same weeks Braiins Pool’s block rewards began to be moved together with those of AntPool, the pool of the mining-machine maker Bitmain; the earliest link that one of them, deadmanoz, has traced is block 817,964, on 22 November 2023. Until 30 June 2026 Braiins Pool’s block templates, the lists of transactions a pool gives its miners to work on, matched or closely resembled AntPool’s, according to the researchers 0xB10C and bboerst, who record the work pools send out; since then they have been its own. As deadmanoz notes, this doesn’t show what the arrangement was, or that AntPool controlled the pool. Lukáš Hozda of Braiins wrote in October 2026 that the pool “is independent and does not direct its hashrateHashrateHow many guesses a second all of Bitcoin's miners make together. More hashrate makes the network harder to attack. to AntPool”.