# `EEVM.Block.Header`
[🔗](https://github.com/mw2000/eevm/blob/main/lib/eevm/block/header.ex#L1)

Ethereum block header — the consensus-critical metadata for a block. A pure
data carrier; validation lives in `EEVM.Block.Processor`.

### Fields

| Field | Description |
|-------|-------------|
| `number` | Block number (height on the chain) |
| `parent_hash` | Keccak hash of the parent header |
| `timestamp` | Block timestamp in seconds since epoch |
| `coinbase` | Address of the block producer (fee recipient) |
| `gas_limit` | Maximum cumulative gas the block may consume |
| `base_fee_per_gas` | EIP-1559 base fee |
| `prev_randao` | RANDAO mix inherited from the beacon chain (post-Merge) |
| `parent_beacon_block_root` | EIP-4788 beacon root pointer from the parent slot |
| `state_root` | Post-execution world-state MPT root |
| `receipts_root` | MPT root of `{rlp(index) => rlp(receipt)}` |
| `transactions_root` | MPT root of `{rlp(index) => rlp(transaction)}` |
| `logs_bloom` | 256-byte bloom summarising every log in the block |
| `gas_used` | Total gas the block's transactions consumed, as declared by the producer |
| `extra_data` | Arbitrary producer bytes (at most 32 bytes on mainnet) |
| `difficulty` | Proof-of-work difficulty (always zero post-Merge) |
| `hash` | Keccak hash of this header, as supplied by the caller (not computed here) |
| `nonce` | 8-byte proof-of-work nonce (all zero post-Merge) |
| `ommers_hash` | Keccak hash of the RLP ommers list (the empty-list hash post-Merge) |
| `blob_gas_used` | EIP-4844 blob gas consumed by the block; `nil` before Cancun |
| `excess_blob_gas` | EIP-4844 running excess blob gas; `nil` before Cancun |

# `t`

```elixir
@type t() :: %EEVM.Block.Header{
  base_fee_per_gas: non_neg_integer(),
  blob_gas_used: non_neg_integer() | nil,
  coinbase: non_neg_integer(),
  difficulty: non_neg_integer(),
  excess_blob_gas: non_neg_integer() | nil,
  extra_data: binary(),
  gas_limit: non_neg_integer(),
  gas_used: non_neg_integer(),
  hash: binary(),
  logs_bloom: binary(),
  nonce: binary(),
  number: non_neg_integer(),
  ommers_hash: binary(),
  parent_beacon_block_root: non_neg_integer(),
  parent_hash: binary(),
  prev_randao: non_neg_integer(),
  receipts_root: binary(),
  state_root: binary(),
  timestamp: non_neg_integer(),
  transactions_root: binary()
}
```

# `empty_ommers_hash`

```elixir
@spec empty_ommers_hash() :: binary()
```

Returns the ommers hash of a block with no ommers, `keccak256(rlp([]))`,
which every post-Merge header carries.

# `new`

```elixir
@spec new() :: t()
```

Returns a zero-initialised header.

# `new`

```elixir
@spec new(keyword()) :: t()
```

Returns a header with the given overrides.

## Example

    iex> header = EEVM.Block.Header.new(number: 18_000_000, gas_limit: 30_000_000)
    iex> {header.number, header.gas_limit}
    {18_000_000, 30_000_000}

---

*Consult [api-reference.md](api-reference.md) for complete listing*