What is a coinbase transaction?
The first payment in every block, created by its miner. It has no inputs and pays out the block reward.
Not to be confused with: the exchange of the same name.
Every block opens with a coinbase transaction, written by the miner who made the block. Unlike an ordinary payment it spends no earlier output: its new bitcoin comes from the block subsidy, and it collects the fees of the block's payments.
Its outputs pay the block rewardBlock rewardWhat a block's miner earns: new bitcoin from the subsidy, plus the fees of every transaction in the block. to the miner or pool, but they cannot be spent for another 100 blocks, a rule called coinbase maturity.
References
- Bitcoin Core, “COINBASE_MATURITY in src/consensus/consensus.h”.