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## `blobBaseFee`

### Signature

```solidity
function blobBaseFee(uint256 newBlobBaseFee) external;
```

### Description

Sets `block.blobbasefee` ([EIP-7516](https://eips.ethereum.org/EIPS/eip-7516)) to `newBlobBaseFee`.

### Parameters

| Parameter        | Type      | Description                   |
|------------------|-----------|-------------------------------|
| `newBlobBaseFee` | `uint256` | The new blob base fee to set  |

### Examples

```solidity [test/BlobBaseFee.t.sol]
// [!include ~/snippets/projects/blob_cheatcodes/test/BlobBaseFee.t.sol]
```

```bash
$ forge test --root src/snippets/projects/blob_cheatcodes --match-contract BlobBaseFeeTest
```

### Gotchas

:::warning
Reading `block.blobbasefee` in the same test function after `vm.blobBaseFee` may still return the old value: the compiler assumes it is constant within a transaction and can reuse an earlier read. Use [`vm.getBlobBaseFee`](/reference/cheatcodes/get-blob-base-fee) instead. See [foundry#6180](https://github.com/foundry-rs/foundry/issues/6180).
:::

### Related Cheatcodes

* [`getBlobBaseFee`](/reference/cheatcodes/get-blob-base-fee) - Gets the current `block.blobbasefee`
* [`fee`](/reference/cheatcodes/fee) - Sets `block.basefee`
* [`blobhashes`](/reference/cheatcodes/blobhashes) - Sets the blob versioned hashes of the current transaction