---
title: "Configuration"
description: "Reference for Base Chain configuration parameters and the roles authorized to change them, grouped into consensus parameters, policy parameters, admin roles, and service roles."
source: https://basehub.org/specifications/configuration/
---
Base configuration is organized into four groups, distinguished by how — and by whom — each value can be altered:

- **Consensus Parameters** — set at genesis, or only movable through privileged accounts or a protocol upgrade.
- **Policy Parameters** — adjustable within protocol-enforced bounds without breaking consensus.
- **Admin Roles** — accounts permitted to upgrade contracts, reassign role ownership, or alter protocol parameters. Usually held in cold/multisig wallets.
- **Service Roles** — accounts that drive everyday operations. Usually hot wallets.

## Consensus Parameters

| Parameter | Description | Administrator |
|-----------|-------------|---------------|
| Batch Inbox Address | L1 address where batcher transactions are posted | Static |
| Batcher Hash | Versioned hash of the authorized batcher sender(s) | [System Config Owner](#admin-roles) |
| Chain ID | Unique chain ID for transaction signature validation | Static |
| Proof Maturity Delay | Time between proving and finalizing a withdrawal. 1 day. | [L1 Proxy Admin](#admin-roles) |
| Respected Game Type | Game type `OptimismPortal` accepts for withdrawal finalization. Aggregate verifier (`621`). | [Guardian](#service-roles) |
| Bond Withdrawal Delay | Time before dispute game bonds can be withdrawn. 1 day. | Static |
| Fee Scalar | Markup on transactions relative to raw L1 data cost. Fee margin between 0%–50%. | [System Config Owner](#admin-roles) |
| Gas Limit | L2 block gas limit. ≤ 200,000,000 gas. | [System Config Owner](#admin-roles) |
| Genesis State | Initial chain state including all predeploy code and storage. Standard predeploys and preinstalls only. | Static |
| L2 Block Time | Interval at which L2 blocks are produced via derivation. 1 or 2 seconds. | [L1 Proxy Admin](#admin-roles) |
| Sequencing Window Size | Max batch submission gap before L1 fallback triggers. 3,600 L1 blocks (12 hours at 12s L1 block time). | Static |
| Start Block | L1 block where `SystemConfig` was first initialized | [L1 Proxy Admin](#admin-roles) |
| Superchain Target | `SuperchainConfig` and `ProtocolVersions` addresses for cross-L2 config. Mainnet or Sepolia. | Static |
| Governance Token | OP governance token. Disabled. | n/a |
| Operator Fee Params | Operator fee scalar and constant for fee calculation. Standard values are 0; non-zero for non-standard configurations such as op-succinct. | [System Config Owner](#admin-roles) |
| DA Footprint Gas Scalar | Scalar for DA footprint calculation | [System Config Owner](#admin-roles) |
| Minimum Base Fee | Minimum base fee on L2 | [System Config Owner](#admin-roles) |

## Policy Parameters

| Parameter | Description | Administrator |
|-----------|-------------|---------------|
| Data Availability Type | Whether the batcher posts data as blobs or calldata. Ethereum (Blobs or Calldata); Alt-DA not supported. | [Batch Submitter](#service-roles) |
| Batch Submission Frequency | Frequency of batcher transaction submissions to L1. ≤ 1,800 L1 blocks (6 hours at 12s L1 block time). | [Batch Submitter](#service-roles) |
| Output Frequency | Frequency of output root submissions to L1. ≤ 43,200 L2 blocks (24 hours at 2s L2 block time); must be non-zero. Deprecated once fault proofs are enabled. | [L1 Proxy Admin](#admin-roles) |

## Admin Roles

| Role | Description | Administers |
|------|-------------|-------------|
| L1 Proxy Admin | `ProxyAdmin` from the latest `op-contracts` release, authorized to upgrade L1 contracts | L1 contracts |
| L1 ProxyAdmin Owner | Authorized to update the L1 Proxy Admin. [0x5a0Aae59D09fccBdDb6C6CcEB07B7279367C3d2A](https://etherscan.io/address/0x5a0Aae59D09fccBdDb6C6CcEB07B7279367C3d2A) | L1 Proxy Admin |
| L2 Proxy Admin | `ProxyAdmin` at `0x4200000000000000000000000000000000000018`, authorized to upgrade L2 contracts | Predeploys |
| L2 ProxyAdmin Owner | Aliased L1 ProxyAdmin Owner; upgrades L2 contracts via `ProxyAdmin`. [0x6B1BAE59D09fCcbdDB6C6cceb07B7279367C4E3b](https://optimistic.etherscan.io/address/0x6B1BAE59D09fCcbdDB6C6cceb07B7279367C4E3b) | L2 Proxy Admin |
| System Config Owner | Authorized to change values in the `SystemConfig` contract | Batch Submitter, Sequencer P2P Signer, Fee Scalar, Gas Limit |

## Service Roles

| Role | Description | Administrator |
|------|-------------|-------------|
| Batch Submitter | Authenticates batches submitted to L1 | [System Config Owner](#admin-roles) |
| Challenger | Interacts with permissioned dispute games. [0x9BA6e03D8B90dE867373Db8cF1A58d2F7F006b3A](https://etherscan.io/address/0x9BA6e03D8B90dE867373Db8cF1A58d2F7F006b3A) | [L1 Proxy Admin](#admin-roles) |
| Guardian | Pauses L1 withdrawals, blacklists dispute games, sets respected game type in `OptimismPortal`. [0x09f7150D8c019BeF34450d6920f6B3608ceFdAf2](https://etherscan.io/address/0x09f7150D8c019BeF34450d6920f6B3608ceFdAf2) | [L1 Proxy Admin](#admin-roles) |
| Proposer | Creates permissioned dispute games on L1. | [L1 Proxy Admin](#admin-roles) |
| Sequencer P2P Signer | Signs unsafe/pre-submitted blocks at the P2P layer | [System Config Owner](#admin-roles) |