Bitcoin mining pools rally behind Stratum V2 to decentralise block templates

Seven of bitcoin’s largest mining pools and infrastructure operators joined the Stratum V2 working group on Thursday, lining up behind a long-stalled protocol upgrade that moves block-template construction from pool operators to individual miners.

ANTPOOL, F2Pool, Foundry, Block Inc, MARA Foundation, Spiderpool and DMND will work alongside the group’s founding members to publish a reference implementation, push hardware vendors to ship Stratum V2 by default, and coordinate adoption across the bitcoin mining stack. The working group, established in 2022 by Czech mining-tech firm Braiins and Block Inc subsidiary Spiral, had spent three years drafting the protocol against muted pool engagement.

That changed this week. ANTPOOL and F2Pool together account for roughly 25 to 35 per cent of global bitcoin hashrate, according to figures cited by Crypto Briefing. With Foundry and MARA Foundation included, the bloc represents what the group described as a meaningful share of total network computational power.

“We’re proud to support the broader adoption of Stratum V2,” ANTPOOL chief executive Andy Zhou said in the announcement. “Aligning around an open, interoperable standard enables the industry to collaborate more effectively and drive improvements in efficiency, security and decentralization.”

Why the protocol matters

Bitcoin’s existing mining protocol, Stratum V1, was designed in 2012 and predates almost every concern that now shapes the network. It runs in plaintext, exposing pool-miner traffic to interception and pool credentials to harvesting. More consequentially, it leaves block-template construction entirely to the pool operator. Miners contribute hashpower. Pools decide which transactions go into the block.

That asymmetry has long worried critics. A handful of large pools effectively choose the network’s transaction set, giving them indirect leverage over fee priority, OFAC compliance pressure, and any future maximal extractable value mechanic. Stratum V2 is engineered to break that lock by allowing miners to construct their own block templates while still drawing payouts through a pool.

“Decentralization is core to our mission,” Spiderpool chief technology officer Kenway Wang said. “Stratum V2 supports this by enabling miner-constructed templates, while also improving efficiency, especially for miners in bandwidth-constrained environments.”

The protocol also introduces end-to-end encryption between pool and miner, denser binary message framing, and lower-latency job dispatch. Crypto Briefing cited working-group estimates that those changes can deliver up to 7.4 per cent higher profitability for miners through reduced rejected shares and stale blocks.

What pools actually commit to

Joining the working group is not the same as deploying V2 in production. Each member is signing on to support specification work, fund a shared open-source reference implementation, and align on testing milestones. Production rollout depends on three parallel tracks. Pool operators must run V2-capable stratum servers. Firmware vendors must ship V2 in ASIC software. And miners must opt into the template-construction mode, which carries operational complexity that smaller operators have largely skipped.

Block Inc’s involvement carries weight on the hardware side. The company manufactures bitcoin-specific mining silicon through its Bitkey and Proto units, alongside Spiral’s specification work. Foundry, owned by Digital Currency Group, runs the largest North American pool by hashrate share and supplies the firmware behind a substantial slice of new ASIC orders.

The Stratum V2 working group projects that V2 will become the default protocol for new ASIC firmware shipments by the end of 2026, taking the share of network hashrate operating under the new standard from roughly a quarter today to between 40 and 60 per cent.

A second push after a slow start

The 2022 launch attracted developer attention but limited pool buy-in. Pools had little near-term commercial reason to surrender template-construction control, and miners themselves had no obvious upgrade path. Three things shifted that calculus. Regulatory scrutiny of pool-level censorship sharpened in the United States and the European Union. The 2024 halving compressed margins and made the 7.4 per cent efficiency claim materially attractive. And on-chain debate around MEV, sandwich attacks and miner extractable revenue made template control a live political issue inside the bitcoin developer community.

Thursday’s expansion is also a signal of who is now willing to be seen on a decentralisation roadmap. ANTPOOL is operated by Bitmain, the dominant ASIC manufacturer, and its endorsement aligns the largest miner-facing brand in the industry with a protocol that, in principle, dilutes pool authority. F2Pool, headquartered in Beijing, is one of bitcoin’s longest-running mining pools.

The working group has yet to publish a deployment timeline beyond the firmware projection. A reference implementation lives on the project’s GitHub and a public specification at stratumprotocol.org. Members will coordinate testing through a shared testnet over the coming months, with the goal of reaching production interoperability before the next halving cycle in 2028.

What’s next

Investors have read the announcement against a softer backdrop for the asset itself. Bitcoin has traded around the $80,000 level this week, with spot ETFs absorbing $277.5m in outflows as positioning re-set ahead of the US-Iran negotiations. Corporate treasury demand has held up by contrast, with Coinbase adding $88m of bitcoin to its balance sheet in the first quarter.

Pool consolidation, censorship pressure and MEV remain the three forces shaping the next phase of bitcoin’s mining landscape. Stratum V2 is the most concrete protocol-level response to all three currently in active development. Whether seven signatures and a reference implementation translate into a dominant standard will depend on how quickly Bitmain, Foundry and Block Inc move from working-group endorsement to default-firmware shipping over the next eighteen months.