Contract Addresses
The tables below list the canonical contract and admin addresses for Base Mainnet and Base Sepolia, with links to the corresponding block explorer.
L2 contract addresses
Section titled “L2 contract addresses”Base Mainnet
Section titled “Base Mainnet”| Name | Address |
|---|---|
| WETH9 | 0x4200000000000000000000000000000000000006 |
| L2CrossDomainMessenger | 0x4200000000000000000000000000000000000007 |
| L2StandardBridge | 0x4200000000000000000000000000000000000010 |
| SequencerFeeVault | 0x4200000000000000000000000000000000000011 |
| OptimismMintableERC20Factory | 0xF10122D428B4bc8A9d050D06a2037259b4c4B83B |
| GasPriceOracle | 0x420000000000000000000000000000000000000F |
| L1Block | 0x4200000000000000000000000000000000000015 |
| L2ToL1MessagePasser | 0x4200000000000000000000000000000000000016 |
| L2ERC721Bridge | 0x4200000000000000000000000000000000000014 |
| OptimismMintableERC721Factory | 0x4200000000000000000000000000000000000017 |
| ProxyAdmin | 0x4200000000000000000000000000000000000018 |
| BaseFeeVault | 0x4200000000000000000000000000000000000019 |
| L1FeeVault | 0x420000000000000000000000000000000000001a |
| EAS | 0x4200000000000000000000000000000000000021 |
| EASSchemaRegistry | 0x4200000000000000000000000000000000000020 |
| LegacyERC20ETH | 0xDeadDeAddeAddEAddeadDEaDDEAdDeaDDeAD0000 |
Base Sepolia
Section titled “Base Sepolia”| Name | Address |
|---|---|
| WETH9 | 0x4200000000000000000000000000000000000006 |
| L2CrossDomainMessenger | 0x4200000000000000000000000000000000000007 |
| L2StandardBridge | 0x4200000000000000000000000000000000000010 |
| SequencerFeeVault | 0x4200000000000000000000000000000000000011 |
| OptimismMintableERC20Factory | 0x4200000000000000000000000000000000000012 |
| GasPriceOracle | 0x420000000000000000000000000000000000000F |
| L1Block | 0x4200000000000000000000000000000000000015 |
| L2ToL1MessagePasser | 0x4200000000000000000000000000000000000016 |
| L2ERC721Bridge | 0x4200000000000000000000000000000000000014 |
| OptimismMintableERC721Factory | 0x4200000000000000000000000000000000000017 |
| ProxyAdmin | 0x4200000000000000000000000000000000000018 |
| BaseFeeVault | 0x4200000000000000000000000000000000000019 |
| L1FeeVault | 0x420000000000000000000000000000000000001a |
| EAS | 0x4200000000000000000000000000000000000021 |
| EASSchemaRegistry | 0x4200000000000000000000000000000000000020 |
| LegacyERC20ETH | 0xDeadDeAddeAddEAddeadDEaDDEAdDeaDDeAD0000 |
Most L2 predeploys share the same address on Base Mainnet and Base Sepolia. The exceptions are network-specific contracts such as OptimismMintableERC20Factory, whose per-network address appears in the relevant table above.
L1 contract addresses
Section titled “L1 contract addresses”Ethereum Mainnet
Section titled “Ethereum Mainnet”Mainnet’s proof contracts were swapped ahead of the Cobalt activation at 1790791200 (September 30, 2026, 18:00 UTC). The AggregateVerifier row now points at a new deployment, and a factory query on 2026-09-30 confirmed that game type 621 already resolves to it. Nitro attestation is handled by NitroValidator, which works with CertManager and P384Verifier; together they take the place of the retired NitroEnclaveVerifier. Anything that pinned the old Mainnet AggregateVerifier or NitroEnclaveVerifier address needs updating.
Unused OP Stack addresses
Section titled “Unused OP Stack addresses”The OP Stack SDK requires the following addresses to be set even though Base does not use them. Pass the zero address for each:
StateCommitmentChainCanonicalTransactionChainBondManager
Ethereum Sepolia
Section titled “Ethereum Sepolia”The Sepolia proof contracts moved with the Cobalt upgrade on 2026-09-23. AggregateVerifier (Multiproof) and ZkVerifier now point at new deployments. The Nitro attestation path is listed as NitroValidator, with CertManager and P384Verifier beside it, in place of the old NitroEnclaveVerifier row. If you pinned any of the old Sepolia addresses, update them. The Mainnet AggregateVerifier and Nitro rows changed later, ahead of the Mainnet activation; see the note above that table.
Base admin addresses
Section titled “Base admin addresses”Base Mainnet
Section titled “Base Mainnet”| Admin Role | Address | Type of Key |
|---|---|---|
| Base Security Council | 0x20AcF55A3DCfe07fC4cecaCFa1628F788EC8A4Dd | Gnosis Safe |
| Batch Sender | 0x5050f69a9786f081509234f1a7f4684b5e5b76c9 | EOA managed by Coinbase Technologies |
| Batch Inbox | 0xff00000000000000000000000000000000008453 | EOA (with no known private key) |
| CB Multisig | 0x9855054731540A48b28990B63DcF4f33d8AE46A1 | Gnosis Safe |
| Output Proposer | 0xc1366Fabe614d42D367A1ecE61821238A1d31cF5 | EOA managed by Coinbase Technologies |
| Proxy Admin Owner (L1) | 0x7bB41C3008B3f03FE483B28b8DB90e19Cf07595c | Gnosis Safe |
| Challenger | 0x819501cdA743a606A93dbEF254FE0D263Ce7d102 | EOA managed by Coinbase Technologies |
| SystemConfig owner | 0x14536667Cd30e52C0b458BaACcB9faDA7046E056 | Gnosis Safe |
| Guardian | 0x7bB41C3008B3f03FE483B28b8DB90e19Cf07595c | Gnosis Safe |
| Incident Multisig | 0x14536667Cd30e52C0b458BaACcB9faDA7046E056 | Gnosis Safe |
| Registrar | 0xd87488Dbb5b6F47cc6c15Dd95Bb60c83D3031b04 | EOA managed by Coinbase Technologies |
Base Sepolia
Section titled “Base Sepolia”| Admin Role | Address | Type of Key |
|---|---|---|
| Base Security Council | 0x6AF0674791925f767060Dd52f7fB20984E8639d8 | Gnosis Safe |
| Batch Sender | 0x6CDEbe940BC0F26850285cacA097C11c33103E47 | EOA managed by Coinbase Technologies |
| Batch Inbox | 0xff00000000000000000000000000000000084532 | EOA (with no known private key) |
| CB Multisig | 0x646132A1667ca7aD00d36616AFBA1A28116C770A | Gnosis Safe |
| Output Proposer | 0xdb84125f2f4229c81c579f41bc129c71b174eb58 | EOA managed by Coinbase Technologies |
| Proxy Admin Owner (L1) | 0x0fe884546476dDd290eC46318785046ef68a0BA9 | Gnosis Safe |
| Challenger | 0xadc09b63a3ac57a2ce86d946617a18df9db029a1 | EOA managed by Coinbase Technologies |
| SystemConfig owner | 0x646132A1667ca7aD00d36616AFBA1A28116C770A | Gnosis Safe |
| Guardian | 0x0fe884546476dDd290eC46318785046ef68a0BA9 | Gnosis Safe |
| Incident Multisig | 0x646132A1667ca7aD00d36616AFBA1A28116C770A | Gnosis Safe |