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    Differences from Ethereum

    Liberty Chain is EVM-equivalent, not merely EVM-compatible. This is an important distinction: EVM-equivalent means the chain implements the same execution environment as Ethereum at the specification level, so virtually all Ethereum tooling, contracts, and libraries work without modification. In practice, 99% of what you build for Ethereum will work identically on Liberty Chain.

    That said, there are a handful of architectural differences that stem from Liberty Chain being a Layer-2 rollup built on the OP Stack. Understanding these differences will help you build more robust applications and avoid unexpected behavior.

    Almost Everything Works

    If your smart contract works on Ethereum, it will work on Liberty Chain. The differences listed below are edge cases that most applications will never encounter. Standard Solidity contracts, ERC token standards, and common libraries like OpenZeppelin deploy and execute identically.

    Key Differences

    Transaction Fees

    On Ethereum, a transaction fee consists of a single component: gas used multiplied by the gas price. On Liberty Chain, transaction fees have two components:

    • L2 execution fee — The cost of executing the transaction on Liberty Chain. This is calculated similarly to Ethereum (gas used multiplied by the L2 gas price) but is significantly cheaper due to the higher throughput of the L2.
    • L1 data fee — The cost of posting the transaction data to Ethereum L1 as part of the rollup's batch submission. This component varies with Ethereum L1 gas prices and the size of your transaction's calldata.

    For most transactions, the L1 data fee is the dominant cost. Applications that optimize calldata size (using fewer bytes, packing data efficiently) will see the greatest fee reductions.

    Block Time

    Liberty Chain produces blocks every 2 seconds, compared to Ethereum's 12-second block time. This means faster transaction confirmations and a more responsive user experience. If your application uses block numbers as a proxy for time, be aware that blocks accumulate approximately 6 times faster than on Ethereum mainnet.

    Opcode Differences

    While all EVM opcodes are supported, a few behave differently due to the L2 architecture:

    • PREVRANDAO — On Ethereum, this returns the beacon chain's RANDAO mix and provides a source of randomness. On Liberty Chain, it returns a sequencer-set value and should not be relied upon for randomness or unpredictability.
    • COINBASE — On Ethereum, this returns the block proposer's address. On Liberty Chain, it returns the address of the fee vault contract where sequencer fees are collected.

    Block Gas Limit

    The block gas limit on Liberty Chain is 60 million gas, which is double Ethereum's 30 million gas limit. This allows for more transactions per block and enables larger, more complex contract interactions within a single block.

    Deposit Transactions

    Liberty Chain introduces a special transaction type: Type 126 deposit transactions. These are transactions that originate on L1 and are executed on L2 as part of the deposit flow (bridging assets from Ethereum to Liberty Chain). They are included in L2 blocks by the sequencer and do not have a traditional sender signature because they are authorized by the L1 bridge contract. Most applications do not need to handle deposit transactions directly.

    L1 Block Information

    Liberty Chain provides access to L1 block data through the L1Block predeploy contract at address 0x4200000000000000000000000000000000000015. This contract exposes L1 block attributes including the block number, timestamp, base fee, and hash. Applications that need to verify L1 state or coordinate with L1 timing can read from this contract.

    No Public Mempool

    Unlike Ethereum, Liberty Chain does not have a public mempool with peer-to-peer transaction gossip. Transactions are submitted directly to the sequencer, which processes them in the order received. This architectural difference means:

    • There is no traditional front-running via mempool observation (though the sequencer can still order transactions).
    • Pending transactions are not visible to other users before inclusion in a block.
    • MEV extraction strategies that rely on mempool monitoring do not apply in the same way.

    What Works Identically

    The vast majority of the Ethereum ecosystem works on Liberty Chain without any changes:

    • Smart contract languages — Solidity and Vyper compile and deploy identically.
    • Token standards — ERC-20, ERC-721, ERC-1155, ERC-4626, and all other ERC standards work without modification.
    • Client libraries — ethers.js, web3.js, viem, and web3.py connect and interact with Liberty Chain using the same APIs as Ethereum.
    • Development frameworks — Hardhat, Foundry, Truffle, and Remix all work by simply configuring the Liberty Chain RPC endpoint.
    • Wallets — MetaMask, WalletConnect, and any EVM-compatible wallet can connect by adding the Liberty Chain network configuration.
    • Libraries — OpenZeppelin contracts, Solady, and other widely-used Solidity libraries deploy and function identically.