Building a candidate block
A pool or solo miner obtains transactions from a node, selects a valid set, constructs the coinbase transaction and calculates a Merkle root for the block header.
Fee rate, dependencies, block weight and policy influence selection, but every included transaction must still satisfy consensus.
Work and shares
Pool participants repeatedly vary header-related data and hash. Shares meet a pool-defined target easier than Bitcoin's network target, providing evidence for payout accounting. A share that also meets the network target is a block candidate.
Coordination trade-offs
Pools reduce payout variance but can concentrate template construction. Protocols and practices that give individual miners more visibility or control over transaction selection aim to reduce that concentration.
Visual recap
From mempool to mined block
Pool accounting and Bitcoin consensus use different difficulty targets.
Node mempool
Block template
Miners hash
Shares measure work
Valid block relayed
Key takeaways
- A block template commits to selected transactions.
- Shares measure work but are not necessarily Bitcoin blocks.
- Pools reduce income variance for miners.
- Every discovered block is independently validated by nodes.
Lesson recap
Check what you learned
Reveal each model answer, then honestly mark whether you understood it or need another review.
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Recall
Why does a pool accept shares that the Bitcoin network would not accept as blocks?
References
