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

# Rollup RPC Methods

The `optimism` API provides methods for interacting with Kona's rollup state and configuration.

## `optimism_outputAtBlock`

Returns the output root at a specific block number, including the L2 block reference, withdrawal storage root, state root, and sync status.

| Client | Method invocation                                               |
| ------ | --------------------------------------------------------------- |
| RPC    | `{"method": "optimism_outputAtBlock", "params": [blockNumber]}` |

### Parameters

* `blockNumber` (`BlockNumberOrTag`): The block number to get the output for. Can be a number, "latest", "earliest", "pending", "safe", or "finalized".

### Returns

`OutputResponse` - An object containing:

* `version` (`string`): The output version hash
* `outputRoot` (`string`): The output root hash
* `blockRef` (`L2BlockInfo`): Reference to the L2 block
* `withdrawalStorageRoot` (`string`): The withdrawal storage root
* `stateRoot` (`string`): The state root
* `syncStatus` (`SyncStatus`): The current sync status of the node

### Example

```js theme={null}
// > {"jsonrpc":"2.0","id":1,"method":"optimism_outputAtBlock","params":["latest"]}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "version": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "outputRoot": "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
    "blockRef": {
      "hash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890",
      "number": 12345,
      "parentHash": "0x9876543210fedcba9876543210fedcba9876543210fedcba9876543210fedcba",
      "timestamp": 1699123456,
      "l1Origin": {
        "hash": "0xfedcba0987654321fedcba0987654321fedcba0987654321fedcba0987654321",
        "number": 18123456
      },
      "sequenceNumber": 42
    },
    "withdrawalStorageRoot": "0x567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234",
    "stateRoot": "0xcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890ab",
    "syncStatus": {
      "current_l1": {
        "hash": "0x1111111111111111111111111111111111111111111111111111111111111111",
        "number": 18123456
      },
      "current_l1_finalized": {
        "hash": "0x2222222222222222222222222222222222222222222222222222222222222222",
        "number": 18123400
      },
      "head_l1": {
        "hash": "0x3333333333333333333333333333333333333333333333333333333333333333",
        "number": 18123460
      },
      "safe_l1": {
        "hash": "0x4444444444444444444444444444444444444444444444444444444444444444",
        "number": 18123450
      },
      "finalized_l1": {
        "hash": "0x5555555555555555555555555555555555555555555555555555555555555555",
        "number": 18123400
      },
      "unsafe_l2": {
        "hash": "0x6666666666666666666666666666666666666666666666666666666666666666",
        "number": 12350,
        "parentHash": "0x7777777777777777777777777777777777777777777777777777777777777777",
        "timestamp": 1699123500,
        "l1Origin": {
          "hash": "0x8888888888888888888888888888888888888888888888888888888888888888",
          "number": 18123460
        },
        "sequenceNumber": 47
      },
      "safe_l2": {
        "hash": "0x9999999999999999999999999999999999999999999999999999999999999999",
        "number": 12345,
        "parentHash": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
        "timestamp": 1699123456,
        "l1Origin": {
          "hash": "0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
          "number": 18123456
        },
        "sequenceNumber": 42
      },
      "finalized_l2": {
        "hash": "0xcccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
        "number": 12340,
        "parentHash": "0xdddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
        "timestamp": 1699123400,
        "l1Origin": {
          "hash": "0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
          "number": 18123400
        },
        "sequenceNumber": 37
      },
      "cross_unsafe_l2": {
        "hash": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
        "number": 12350,
        "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000001",
        "timestamp": 1699123500,
        "l1Origin": {
          "hash": "0x0000000000000000000000000000000000000000000000000000000000000002",
          "number": 18123460
        },
        "sequenceNumber": 47
      },
      "local_safe_l2": {
        "hash": "0x0000000000000000000000000000000000000000000000000000000000000003",
        "number": 12345,
        "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000004",
        "timestamp": 1699123456,
        "l1Origin": {
          "hash": "0x0000000000000000000000000000000000000000000000000000000000000005",
          "number": 18123456
        },
        "sequenceNumber": 42
      }
    }
  }
}
```

## `optimism_syncStatus`

Returns the current synchronization status of the rollup node, including information about L1 and L2 block states.

| Client | Method invocation                                 |
| ------ | ------------------------------------------------- |
| RPC    | `{"method": "optimism_syncStatus", "params": []}` |

### Returns

`SyncStatus` - An object containing detailed sync information:

* `current_l1` (`BlockInfo`): The current L1 block that derivation is idled at
* `current_l1_finalized` (`BlockInfo`): The current L1 finalized block (legacy/deprecated)
* `head_l1` (`BlockInfo`): The L1 head block reference
* `safe_l1` (`BlockInfo`): The L1 safe head block reference
* `finalized_l1` (`BlockInfo`): The finalized L1 block reference
* `unsafe_l2` (`L2BlockInfo`): The unsafe L2 block reference (absolute tip)
* `safe_l2` (`L2BlockInfo`): The safe L2 block reference (derived from L1)
* `finalized_l2` (`L2BlockInfo`): The finalized L2 block reference
* `cross_unsafe_l2` (`L2BlockInfo`): Cross-unsafe L2 block with verified cross-L2 dependencies
* `local_safe_l2` (`L2BlockInfo`): Local safe L2 block derived from L1, not yet cross-verified

### Example

```js theme={null}
// > {"jsonrpc":"2.0","id":1,"method":"optimism_syncStatus","params":[]}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "current_l1": {
      "hash": "0x1111111111111111111111111111111111111111111111111111111111111111",
      "number": 18123456
    },
    "current_l1_finalized": {
      "hash": "0x2222222222222222222222222222222222222222222222222222222222222222",
      "number": 18123400
    },
    "head_l1": {
      "hash": "0x3333333333333333333333333333333333333333333333333333333333333333",
      "number": 18123460
    },
    "safe_l1": {
      "hash": "0x4444444444444444444444444444444444444444444444444444444444444444",
      "number": 18123450
    },
    "finalized_l1": {
      "hash": "0x5555555555555555555555555555555555555555555555555555555555555555",
      "number": 18123400
    },
    "unsafe_l2": {
      "hash": "0x6666666666666666666666666666666666666666666666666666666666666666",
      "number": 12350,
      "parentHash": "0x7777777777777777777777777777777777777777777777777777777777777777",
      "timestamp": 1699123500,
      "l1Origin": {
        "hash": "0x8888888888888888888888888888888888888888888888888888888888888888",
        "number": 18123460
      },
      "sequenceNumber": 47
    },
    "safe_l2": {
      "hash": "0x9999999999999999999999999999999999999999999999999999999999999999",
      "number": 12345,
      "parentHash": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
      "timestamp": 1699123456,
      "l1Origin": {
        "hash": "0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
        "number": 18123456
      },
      "sequenceNumber": 42
    },
    "finalized_l2": {
      "hash": "0xcccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
      "number": 12340,
      "parentHash": "0xdddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
      "timestamp": 1699123400,
      "l1Origin": {
        "hash": "0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
        "number": 18123400
      },
      "sequenceNumber": 37
    },
    "cross_unsafe_l2": {
      "hash": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
      "number": 12350,
      "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000001",
      "timestamp": 1699123500,
      "l1Origin": {
        "hash": "0x0000000000000000000000000000000000000000000000000000000000000002",
        "number": 18123460
      },
      "sequenceNumber": 47
    },
    "local_safe_l2": {
      "hash": "0x0000000000000000000000000000000000000000000000000000000000000003",
      "number": 12345,
      "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000004",
      "timestamp": 1699123456,
      "l1Origin": {
        "hash": "0x0000000000000000000000000000000000000000000000000000000000000005",
        "number": 18123456
      },
      "sequenceNumber": 42
    }
  }
}
```

## `optimism_rollupConfig`

Returns the rollup configuration parameters that define the rollup chain's behavior and properties.

| Client | Method invocation                                   |
| ------ | --------------------------------------------------- |
| RPC    | `{"method": "optimism_rollupConfig", "params": []}` |

### Returns

`RollupConfig` - An object containing the complete rollup configuration:

* `genesis` (`ChainGenesis`): The genesis state of the rollup
* `blockTime` (`number`): The block time of the L2 in seconds
* `maxSequencerDrift` (`number`): Maximum sequencer drift in seconds
* `seqWindowSize` (`number`): The sequencer window size
* `channelTimeout` (`number`): Number of L1 blocks between channel open/close
* `graniteChannelTimeout` (`number`): Channel timeout after Granite hardfork
* `l1ChainId` (`number`): The L1 chain ID
* `l2ChainId` (`number`): The L2 chain ID
* `batchInboxAddress` (`string`): L1 address where batches are sent
* `depositContractAddress` (`string`): L1 address for deposits
* `l1SystemConfigAddress` (`string`): L1 address for system config
* `protocolVersionsAddress` (`string`): L1 address for protocol versions
* Additional configuration fields for hardforks, fees, and interoperability

### Example

```js theme={null}
// > {"jsonrpc":"2.0","id":1,"method":"optimism_rollupConfig","params":[]}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "genesis": {
      "l1": {
        "hash": "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
        "number": 18000000
      },
      "l2": {
        "hash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890",
        "number": 0,
        "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "timestamp": 1699000000,
        "l1Origin": {
          "hash": "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
          "number": 18000000
        },
        "sequenceNumber": 0
      },
      "l2Time": 1699000000,
      "systemConfig": {
        "batcherAddr": "0x1234567890123456789012345678901234567890",
        "overhead": "0x00000000000000000000000000000000000000000000000000000000000000bc",
        "scalar": "0x00000000000000000000000000000000000000000000000000000000000f4240",
        "gasLimit": 30000000
      }
    },
    "blockTime": 2,
    "maxSequencerDrift": 600,
    "seqWindowSize": 3600,
    "channelTimeout": 300,
    "graniteChannelTimeout": 50,
    "l1ChainId": 1,
    "l2ChainId": 10,
    "batchInboxAddress": "0xff00000000000000000000000000000000000010",
    "depositContractAddress": "0xbEb5Fc579115071764c7423A4f12eDde41f106Ed",
    "l1SystemConfigAddress": "0x229047fed2591dbec1eF1118d64F7aF3dB9EB290",
    "protocolVersionsAddress": "0x8062AbC286f5e7D9428a0Ccb9AbD71e50d93b935",
    "superchainConfigAddress": "0x95703e0982140D16f8ebA6d158FccEde42f04a4C",
    "blobs_data": 1710374400,
    "interopMessageExpiryWindow": 3600,
    "chainOpConfig": {
      "canyon_denominator": 250,
      "canyon_elasticity": 6
    }
  }
}
```

## `optimism_version`

Returns the software version of the Kona rollup node.

| Client | Method invocation                              |
| ------ | ---------------------------------------------- |
| RPC    | `{"method": "optimism_version", "params": []}` |

### Returns

`string` - The version string of the Kona software (e.g., "0.1.0")

### Example

```js theme={null}
// > {"jsonrpc":"2.0","id":1,"method":"optimism_version","params":[]}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0.1.0"
}
```

## Deprecated Methods

### `optimism_safeHeadAtL1Block`

This RPC endpoint is **not supported** in Kona. It was used to track the safe head for every L1 block, but this is no longer necessary post-interop. Calling this method will return a "Method not found" error.

| Client | Method invocation                                                   |
| ------ | ------------------------------------------------------------------- |
| RPC    | `{"method": "optimism_safeHeadAtL1Block", "params": [blockNumber]}` |

### Returns

This method returns an error with code `-32601` (Method not found).