Bitcoin Mining Pool Centralization: Nakamoto Coefficient & HHI Tracker

Template sovereignty: who actually builds the block?

Hashrate share tells you who finds blocks — not who decides what goes in them. On most pools the operator builds the block template and the miner only supplies proof-of-work, so the operator chooses which transactions confirm. Over the last month just 4.63% of Bitcoin's hashrate mined on a pool that lets the miner build its own block template: OCEAN (3.05%), Braiins Pool (1.56%), Public Pool (0.02%) — via Stratum V2 job declaration, OCEAN's DATUM, or a self-hostable / peer-to-peer pool. On the other 94.36% of identified hashrate the pool operator builds the template and picks the transactions.

Capability footprint, not confirmed adoption. This is the share of hashrate on pools that permit miner-built templates, not blocks proven to use it. On P2Pool, Public Pool and self-hosted pools that is the default; on Braiins Pool and OCEAN it is opt-in (Stratum V2 job declaration and DATUM) and still lightly adopted, so the share of blocks the miner actually built is smaller — under about 1% today. It also cannot see self-hosted solo miners, who are unattributable (~1.01% “unknown”). Read 4.63% as the addressable ceiling on today's pools, not the achieved figure. Live shares from mempool.space, as of 2026-07-28.