Hemi

Why is the project listed in others?

The proof system isn't fully functional

Consequence: projects without a proper proof system fully rely on single entities to safely update the state. A malicious proposer can finalize an invalid state, which can cause loss of funds.

Learn more about the recategorisation here.

Value Secured

2024 Sep 10 — 2025 Jul 01

View TVS breakdown

Total value securedTotal

$3.79 M1.52%

Canonically BridgedCanonically Bridged ValueCanonical

$3.79 M1.52%

Natively MintedNatively Minted TokensNative

$0.000.00%

Externally BridgedExternally Bridged ValueExternal

$0.000.00%

View TVS breakdown

Activity

Onchain costs

The section shows the operating costs that L2s pay to Ethereum.

2024 Sep 09 — 2025 Jun 30

Show data posted

1 year total cost

$39.67 K

Avg cost per L2 UOP

$0.043365

1 year data posted

1.84 GiB

Avg size per L2 UOP

2.11 KiB

Liveness

The chart illustrates how "live" the project's operators are by displaying how frequently they submit transactions of the selected type and if these intervals deviate from their typical schedule.

2025 Jun 01 — Jul 01

30D avg. tx data subs. interval

16 minutes

30D avg. state updates interval

24 minutes

Past 30 days anomalies

Risk summary

Sequencer failureState validationData availabilityExit windowProposer failure

Sequencer failure

Self sequence

In the event of a sequencer failure, users can force transactions to be included in the project’s chain by sending them to L1. There can be up to a 12h delay on this operation.

State validation

None

Currently the system permits invalid state roots. More details in project overview.

Data availability

Onchain

All of the data needed for proof construction is published on Ethereum L1.

Exit window

None

There is no window for users to exit in case of an unwanted regular upgrade since contracts are instantly upgradable.

Proposer failure

Cannot withdraw

Only the whitelisted proposers can publish state roots on L1, so in the event of failure the withdrawals are frozen.

Rollup stage

Hemi is not even a

Stage 0

project.

Learn more about Rollup stages

Please keep in mind that these stages do not reflect rollup security, this is an opinionated assessment of rollup maturity based on subjective criteria, created with a goal of incentivizing projects to push toward better decentralization. Each team may have taken different paths to achieve this goal.

Data availability

All data required for proofs is published on chain

All the data that is used to construct the system state is published on chain in the form of cheap blobs or calldata. This ensures that it will be available for enough time.

Learn more about the DA layer here:

Ethereum

State validation

No state validation

OP Stack projects can use the OP fault proof system, already being deployed on some. This project though is not using fault proofs yet and is relying on the honesty of the permissioned Proposer and Challengers to ensure state correctness. The smart contract system permits invalid state roots.

Funds can be stolen if an invalid state root is submitted to the system (CRITICAL).

L2OutputOracle.sol - source code, deleteL2Outputs function

Operator

The system has a centralized operator

The operator is the only entity that can propose blocks. A live and trustworthy operator is vital to the health of the system.

MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.

Users can force any transaction

Because the state of the system is based on transactions submitted on the underlying host chain and anyone can submit their transactions there it allows the users to circumvent censorship by interacting with the smart contract on the host chain directly.

Withdrawals

Regular messaging

The user initiates L2->L1 messages by submitting a regular transaction on this chain. When the block containing that transaction is settled, the message becomes available for processing on L1. The process of block finalization takes a challenge period of 1d to complete.

Funds can be frozen if the centralized validator goes down. Users cannot produce blocks themselves and exiting the system requires new block production (CRITICAL).

Forced messaging

If the user experiences censorship from the operator with regular L2->L1 messaging they can submit their messages directly on L1. The system is then obliged to service this request or halt all messages, including forced withdrawals from L1 and regular messages initiated on L2. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular message.

Forced withdrawal from an OP Stack blockchain

Other considerations

EVM compatible smart contracts are supported

OP stack chains are pursuing the EVM Equivalence model. No changes to smart contracts are required regardless of the language they are written in, i.e. anything deployed on L1 can be deployed on L2.

Introducing EVM Equivalence

Permissions

A dashboard to explore contracts and permissions

Go to Disco

Explore in Disco

Ethereum

Roles:

Challenger EOA 1

Allowed to challenge or delete state roots proposed by a Proposer.

Guardian EOA 1

Allowed to pause withdrawals. In op stack systems with a proof system, the Guardian can also blacklist dispute games and set the respected game type (permissioned / permissionless).

Proposer 0x2BD4…659e

Allowed to post new state roots of the current layer to the host chain.

Sequencer 0x6511…2e7A

Allowed to commit transactions from the current layer to the host chain.

Actors:

GnosisSafe 0x8434…Ea69

A Multisig with 3/8 threshold.
Can upgrade with no delay
- OptimismMintableERC20Factory
  
  via
  - acting via ProxyAdmin
- SuperchainConfig
  
  via
  - acting via ProxyAdmin
- OptimismPortal
  
  via
  - acting via ProxyAdmin
- SystemConfig
  
  via
  - acting via ProxyAdmin
- L1StandardBridge
  
  via
  - acting via ProxyAdmin
- L2OutputOracle
  
  via
  - acting via ProxyAdmin
- L1ERC721Bridge
  
  via
  - acting via ProxyAdmin
- L1CrossDomainMessenger
  
  via
  - acting via ProxyAdmin
Can interact with AddressManager
- set and change address mappings
  
  via
  - acting via ProxyAdmin

Participants (8):

0xdFd8…61d4 0x3dAd…2CD9 0xce1a…b04c 0xB862…2A77 0x5cCf…5091 0xAd43…7610 0x9aCa…6FFa 0xb972…C85b

EOA 1 0xc0E7…cdDF

Can interact with SystemConfig
- it can update the preconfer address, the batch submitter (Sequencer) address and the gas configuration of the system
A Challenger - acting directly
A Guardian - acting directly

Smart contracts

A dashboard to explore contracts and permissions

Go to Disco

Explore in Disco

A diagram of the smart contract architecture

Ethereum

OptimismPortal 0x39a0…4D7e Implementation (Upgradable)Admin

The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe
- guardian: EOA 1
This contract stores the following tokens: ETH.

Can be upgraded by:

GnosisSafe with no delay

SystemConfig 0x5ae6…03c3 Implementation (Upgradable)Admin

Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe
- batcherHash: EOA 3
- owner: EOA 1

Can be upgraded by:

GnosisSafe with no delay

L2OutputOracle 0x6daF…0d51 Implementation (Upgradable)Admin

Contains a list of proposed state roots which Proposers assert to be a result of block execution. Currently only the PROPOSER address can submit new state roots.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe
- challenger: EOA 1
- proposer: EOA 2

Can be upgraded by:

GnosisSafe with no delay

SuperchainConfig 0x1514…2aB8 Implementation (Upgradable)Admin

This is NOT the shared SuperchainConfig contract of the OP stack Superchain but rather a local fork. It manages the PAUSED_SLOT, a boolean value indicating whether the local chain is paused, and GUARDIAN_SLOT, the address of the guardian which can pause and unpause the system.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe
- guardian: EOA 1

Can be upgraded by:

GnosisSafe with no delay

L1StandardBridge 0x5eaa…191e Implementation (Upgradable)Admin

The main entry point to deposit ERC20 tokens from host chain to this chain.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe
This contract can store any token.

Can be upgraded by:

GnosisSafe with no delay

L1ERC721Bridge 0xa446…edE0 Implementation (Upgradable)Admin

Used to bridge ERC-721 tokens from host chain to this chain.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe

Can be upgraded by:

GnosisSafe with no delay

L1CrossDomainMessenger 0xF005…b050 Implementation (Upgradable)Admin

Sends messages from host chain to this chain, and relays messages back onto host chain. In the event that a message sent from host chain to this chain is rejected for exceeding this chain’s epoch gas limit, it can be resubmitted via this contract’s replay function.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe

Can be upgraded by:

GnosisSafe with no delay

OptimismMintableERC20Factory 0x0262…342C Implementation (Upgradable)Admin

A helper contract that generates OptimismMintableERC20 contracts on the network it’s deployed to. OptimismMintableERC20 is a standard extension of the base ERC20 token contract designed to allow the L1StandardBridge contracts to mint and burn tokens. This makes it possible to use an OptimismMintablERC20 as this chain’s representation of a token on the host chain, or vice-versa.

Roles:
- admin: ProxyAdmin; ultimately GnosisSafe

Can be upgraded by:

GnosisSafe with no delay

ProxyAdmin 0xbE81…FB30

Roles:
- owner: GnosisSafe

Value Secured is calculated based on these smart contracts and tokens:

Generic escrow 0x5eaa…191e Implementation (Upgradable)Admin

Main entry point for users depositing ERC20 token that do not require custom gateway.

Can be upgraded by:

ProxyAdmin with no delay

Escrow for ETH 0x39a0…4D7e Implementation (Upgradable)Admin

Main entry point for users depositing ETH.

Can be upgraded by:

ProxyAdmin with no delay

The current deployment carries some associated risks:

Funds can be stolen if a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL).

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Why is the project listed in others?

Funds can be stolen if

Funds can be frozen if

MEV can be extracted if