> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qu.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# BlockTag

```ts theme={null}
type BlockTag: BigNumberish | string;
```

A **BlockTag** specifies a specific block.

**numeric value** - specifies the block height, where the genesis block is block 0; many operations accept a negative
value which indicates the block number should be deducted from the most recent block. A numeric value may be a
`number`, `bigint`, or a decimal of hex string.

**blockhash** - specifies a specific block by its blockhash; this allows potentially orphaned blocks to be specifed,
without ambiguity, but many backends do not support this for some operations.

## Source

[providers/provider.ts:43](https://github.com/dominant-strategies/quais.js/blob/c1c12d43f9d34c6baad2b0542bd6d0acd6fefcbf/src/providers/provider.ts#L43)