Coinbase Transaction
The coinbase transaction is the protocol-only block-reward mint — the chain’s single minting path. Every block, the protocol synthesizes exactly one coinbase transaction as the first transaction in the block; it credits the block reward to the proposer (and, under delegated bonds, to the delegate owner) with no sender debit — this is how new ANM enters supply per the emission schedule.
The Payload Type for Coinbase is 8.
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The coinbase transaction has no real sender. Its signer is the all-zero Treasury sentinel address — a
keyless identity that holds zero balance and is never debited — so the transaction is unsigned and carries no
fee. Because no key can sign for the Treasury, a coinbase cannot be forged: the mempool rejects any coinbase
transaction at intake, and block validation accepts a coinbase only as the first transaction in a block
and only with the exact amount fixed by the emission schedule. Every other transaction type (including
the batch transfer) always has a real, balance-checked, debited
sender, so coin creation lives behind this single protocol-only type.
Payload Structure
The coinbase transaction has a payload that consists of the following fields:
| Field | Size |
|---|---|
| Number of Recipients | Variant |
| Recipients Address 1 | 21 bytes |
| Recipients Amount 1 | Variant |
| … | … |
| Recipients Address N | 21 bytes |
| Recipients Amount N | Variant |
- Number of Recipients specifies how many recipients receive the minted reward (1 or 2: the proposer, plus the delegate owner when the proposer is a delegated validator)
- Recipients Address 1 to N are the account addresses that receive the minted amounts
- Recipients Amount 1 to N are the amounts of coins minted to each corresponding recipient
There is no sender field — the implicit sender is the Treasury sentinel, which mints rather than transfers.
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