Coinbase Transaction
mining · transaction · issuance
The first transaction in a block, used to assign the block subsidy and collected transaction fees.
1.general
A coinbase transaction is the first transaction in a proof-of-work block. Unlike an ordinary transaction, its special input does not spend a previous UTXO; it creates the permitted block subsidy and assigns that value together with the block's transaction fees.
2.rules
Consensus limits the created amount, and Bitcoin-family networks require coinbase outputs to mature for a set number of blocks before they can be spent. Miners also place block-specific data in the coinbase input, often including an extra nonce used during proof-of-work search.
3.distinction
The term predates and is unrelated to Coinbase, the cryptocurrency exchange. A block can remain valid if its miner claims less than the allowed reward; it becomes invalid if the coinbase creates more than consensus permits.
Related terms
Block Reward
→The subsidy and transaction fees a proof-of-work block is permitted to assign to its miner.
mining · distribution
Mining
→Proof-of-work block production in which miners build candidate blocks and search for a header hash below the network target.
mining · proof-of-work
Transaction
→A record submitted to a blockchain to make a payment or another permitted change.
blockchain · technical
Unspent Transaction Output (UTXO)
→A discrete spendable output on a UTXO blockchain, similar to a digital coin that must be spent whole.
technical · blockchain
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