When I connect to a miner, I recieve a 'job', process that 'job', and send back 'shares'. Somehow this means that I earn Monero for my investment in GPUs and electricity.

What is actually happening here?

  • It's because the work you get has already the pool's address included in the coinbase transaction. Commented Oct 21, 2016 at 15:09

2 Answers 2


When you mine, you try to solve a puzzle. In a simple description, you choose a number, any number, hash it together with some info for the block you want to include in the blockchain, and then check if the resulting hash conforms to the rules. This puzzle is designed in such a way that a difficulty level can be set for its solution.

When you mine for the pool, you are doing normal POW and comparing it to the pool's difficulty, which is lower than the current blockchain diff. When the work satisfies the pool's diff you have found a share and you send it to the pool to prove you are working on the job you got.

The pool then checks if your share is valid for your diff AND sees if it satisfies the diff needed to solve a block. Eventually someone will going to submit a share that solves a block and the reward is divided between all the shares.

These shares represent the actual share of work you have contributed for the pool and so you are rewarded accordingly.

  • 2
    What prevent the pool user to check the work before sending it to the pool and if it solve a block, sending it directly and avoid sharing reward?
    – ant Bldel
    Commented Oct 20, 2016 at 21:27

Simply speaking your shares are used to approximate your contribution (work) in proportion to the work performed by the rest of the pool.

When a block is found by your pool the block reward and transaction fees for that block are divided proportionally to your contribution to the work performed by those in the pool.

The larger the pool the smaller your share will be in proportion to the total pool hash rate. This means that your mining reward will be smaller at large pools but you will receive rewards at far greater frequency (less variance) compared to mining at a smaller pool where blocks are found less often.

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