When a block is found, the pool calculates each miner's PPLNS reward and builds a merkle tree from the data. The merkle root is committed on-chain as an OP_RETURN output in the coinbase transaction — the same transaction that pays miners.

To verify your reward, the system reconstructs the merkle proof path from your leaf to the root and checks it against the on-chain commitment. If the proof passes, your reward calculation is mathematically guaranteed to match what was committed at the time the block was mined.

This makes GorillaPool the first mining pool where you don't have to trust the operator — you can verify every payout yourself.