The biggest decentralization move bitcoin mining has seen in years just happened quietly, with seven of the biggest pools agreeing to support the same open standard.
Foundry, AntPool, F2Pool, SpiderPool, MARA Pool, Block Inc and DMND have all joined the Stratum V2 working group, the group announced last week.
Stratum V2 is an open source protocol that controls how mining pools communicate with the individual miners in those pools. The biggest practical change it introduces is letting individual miners construct their own block templates, meaning that the choice of which transactions are included in each new block rests with the miner rather than the pool operator.
Foundry alone controls 34.2% of the global bitcoin hash rate, AntPool another 14.2%, F2Pool 11.3% and SpiderPool 10.5%, with MARA Pool adding 4.7% per Hashrate Index data. Along with the rest of the Stratum V2 signatories, the seven pools that now support the standard represent close to 75% of all bitcoin hashrate.
Under the current Stratum V1 standard, the transaction selection for almost every new block rests with the pool operators rather than the individual miners actually doing the work. This concentration has been the most vocal structural concern of modern mining for the past two years.
Stratum V2 doesn’t change hashrate concentration, but it does change who decides what goes into each block, which is the part the Bitcoin community actually cares about.
A single pool controlling more than 30% of the hashrate is less than ideal, since the same pool that determines the transaction order for that proportion of blocks is the actual risk people are pointing to.
The protocol has existed since 2022, when Braiins and Spiral co-founded the working group. Until now, it had been treated as a niche side project with limited adoption. The association between Foundry and AntPool gives it real scope, and the working group defines the move as the start of a new phase of accelerated implementation.
The timing also matches what the wider mining cohort is doing. CoinShares estimates that up to 20% of miners are currently unprofitable, with the hashprice (the revenue a miner earns per unit of computing power) at $38.57 per petahash per second per day, at or near break-even for operators running mid-generation hardware.
The difficulty level is set to increase again on May 15 from 132.47T to 135.64T per CoinWarz. Network hashrate is now at 998 exahashes per second.
