Coinbase Transaction

Definition

The coinbase transaction is the special first transaction in a Bitcoin block through which the miner claims the permitted block subsidy and transaction fees. Unlike an ordinary transaction, it does not spend previously created outputs through a normal input. Its distinctive input contains block-related data rather than authorization to spend another person's funds. The total value of its outputs cannot exceed the allowable reward, although a miner may claim less. Coinbase outputs must mature for 100 blocks before they can be spent, reducing problems associated with rewards from blocks that later leave the accepted chain. A mining pool can direct the reward to addresses under its control and distribute participant payouts separately. The term is part of Bitcoin's transaction design and should not be confused with the cryptocurrency exchange that uses the same word as its company name.