> ## Documentation Index
> Fetch the complete documentation index at: https://zksync-sdk.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# zks_ RPC

> Public ZKsync zks_ RPC methods exposed on the adapters via <code>client.zks</code> (Bridgehub address, L2→L1 log proofs, receipts with <code>l2ToL1Logs</code>).

### Standard Ethereum RPC (`eth_*`)

Use your base library for all <code>`eth_*`</code> methods.
The <code>client.zks</code>
surface only covers ZKsync-specific RPC (<code>zks\_\*</code>).
For standard Ethereum JSON-RPC (e.g., <code>eth\_call</code>, <code>eth\_getLogs</code>, <code>eth\_getBalance</code>),
call them through your chosen library (`ethers` or `viem`).

## zks\_ Interface

```ts theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
interface ZksRpc {
  getBridgehubAddress(): Promise<Address>;
  getL2ToL1LogProof(txHash: Hex, index: number): Promise<ProofNormalized>;
  getReceiptWithL2ToL1(txHash: Hex): Promise<ReceiptWithL2ToL1 | null>;
}
```

## Methods

### `getBridgehubAddress() → Promise<Address>`

Fetch the on-chain **Bridgehub** contract address.

```ts theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
const addr = await client.zks.getBridgehubAddress();
```

### `getL2ToL1LogProof(txHash: Hex, index: number) → Promise<ProofNormalized>`

Return a normalized proof for the **L2→L1 log** at `index` in `txHash`.

<ParamField name="txHash" type="Hex" required>
  L2 transaction hash that emitted one or more L2→L1 logs.
</ParamField>

<ParamField name="index" type="number" required>
  Zero-based index of the target L2→L1 log within the transaction.
</ParamField>

```ts theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
const proof = await client.zks.getL2ToL1LogProof(l2TxHash, 0);
/*
{
  id: bigint,
  batchNumber: bigint,
  proof: Hex[]
}
*/
```

<Info>
  If a proof isn’t available yet, this method throws a typed <code>STATE</code> error. Poll based on
  your app’s cadence.
</Info>

### `getReceiptWithL2ToL1(txHash: Hex) → Promise<ReceiptWithL2ToL1 | null>`

Fetch the transaction receipt; the returned object **always** includes `l2ToL1Logs` (empty array if none).

```ts theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
const rcpt = await client.zks.getReceiptWithL2ToL1(l2TxHash);
console.log(rcpt?.l2ToL1Logs); // always an array
```

## Types (overview)

```ts theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
type ProofNormalized = {
  id: bigint;
  batchNumber: bigint;
  proof: Hex[];
};

type ReceiptWithL2ToL1 = {
  // …standard receipt fields…
  l2ToL1Logs: unknown[];
};
```

## Usage

<CodeGroup>
  ```ts title="ethers" theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
  import { JsonRpcProvider, Wallet } from 'ethers';
  import { createEthersClient } from '@dutterbutter/zksync-sdk/ethers';

  const l1 = new JsonRpcProvider(process.env.ETH_RPC!);
  const l2 = new JsonRpcProvider(process.env.ZKSYNC_RPC!);
  const signer = new Wallet(process.env.PRIVATE_KEY!, l1);

  const client = createEthersClient({ l1, l2, signer });

  // Public RPC surface:
  const bridgehub = await client.zks.getBridgehubAddress();
  ```

  ```ts title="viem" theme={"theme":{"light":"vitesse-light","dark":"tokyo-night"}}
  import { createPublicClient, http } from "viem";
  import { createViemClient } from "@dutterbutter/zksync-sdk/viem";

  const l1 = createPublicClient({ transport: http(process.env.ETH_RPC!) });
  const l2 = createPublicClient({ transport: http(process.env.ZKSYNC_RPC!) });

  // Provide a WalletClient with an account for L1 operations.
  const l1Wallet = /* your WalletClient w/ account */;

  const client = createViemClient({ l1, l2, l1Wallet });

  // Public RPC surface:
  const bridgehub = await client.zks.getBridgehubAddress();
  ```
</CodeGroup>