Choose token

Canonically Bridged Tokens (Top 15)

LoopringCoin V2 (LRC)
Ether (ETH)
Wrapped liquid staked Ether 2.0 (wstETH)
Immutable X (IMX)
Rocket Pool ETH (rETH)
Wrapped BTC (WBTC)
Tether USD (USDT)
Mask Network (MASK)
ChainLink Token (LINK)
Ethereum Name Service (ENS)
Dai Stablecoin (DAI)
Decentraland MANA (MANA)
Matic Token (MATIC)


DeFi Port is Live on Loopring

2022 Sep 27th

Dutch auctions, lending, and other DeFi functions can be performed on Loopring.

Learn more

Loopring Supports NFTs

2021 Aug 24th

Loopring supports NFT minting, trading, and transfers.

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Loopring’s ZK Rollup AMM is Live

2020 Dec 2nd

Improved implementation, enabling gas-free instant swaps and liquidity changes.

Learn more

Loopring Protocol 3.6 Pre-release

2020 Sep 22nd

Enhancements in transfers, order-book trading and AMM swap.

Learn more

Loopring Supports Payments

2020 Jun 6th

Support for ERC20 transfers is live on Loopring.

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Loopring DEX is online

2020 Feb 27th

ZK Rollup trading is live, as Loopring launches their order book based exchange.

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Loopring ZK Rollup is live

2019 Dec 4th

Loopring Protocol 3.0 is fully operational with support for orderbook trading on WeDex.

Learn more
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Loopring’s ZK Rollup L2 solution aims to offer the same security guarantees as Ethereum mainnet, with a big scalability boost: throughput increased by 1000x, and cost reduced to just 0.1% of L1.

If you find something wrong on this page you can submit an issue or edit the information.

Risk analysis

Sequencer failureState validationData availabilityUpgradeabilityProposer failure

State validation

ZK proofs (SN)

zkSNARKS are zero knowledge proofs that ensure state correctness, but require trusted setup.

Data availability

On chain

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



The code that secures the system can be changed arbitrarily and without notice.

Sequencer failure

Force via L1

Users can force the sequencer to include a withdrawal transaction by submitting a request through L1 with a 0.02 ETH fee. If the sequencer is down for more than 15d, users can use the exit hatch to withdraw their funds. The sequencer can censor individual deposits, but in such case after 15d users can get their funds back.

Proposer failure

Use escape hatch

Users are able to trustlessly exit by submitting a Merkle proof of funds.

Rollup stage

LoopringLoopring is a
Stage 0
ZK Rollup.
The requirement for available node software is under review
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.


Validity proofs ensure state correctness

Each update to the system state must be accompanied by a ZK proof that ensures that the new state was derived by correctly applying a series of valid user transactions to the previous state. These proofs are then verified on Ethereum by a smart contract.

  1. Operators - Loopring design doc

Zero knowledge SNARK cryptography is used

Despite their production use zkSNARKs are still new and experimental cryptography. Cryptography has made a lot of advancements in the recent years but all cryptographic solutions rely on time to prove their security. In addition zkSNARKs require a trusted setup to operate.

  • Funds can be stolen if the cryptography is broken or implemented incorrectly.

  1. Operators - Loopring design doc

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 calldata. This ensures that it will always be available when needed.

  1. Introduction - Loopring design doc


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.

  1. ExchangeV3.sol#L315-L322 - Etherscan source code, submitBlocks function
  2. LoopringIOExchangeOwner.sol#L123-L126 - Etherscan source code, hasAccessTo function call

Users can force exit the system

Force exit allows the users to escape censorship by withdrawing their funds. The system allows users to force the withdrawal of funds by submitting a request directly to the contract on-chain. The request must be served within a defined time period. If this does not happen, the system will halt regular operation and permit trustless withdrawal of funds.

  • Users can be censored if the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system.

  1. Forced Withdrawals - Loopring design doc
  2. Forced Request Handling - Loopring design doc


Regular exit

The user initiates the withdrawal by submitting a regular transaction on this chain. When the block containing that transaction is proven the funds become available for withdrawal on L1. Finally the user submits an L1 transaction to claim the funds. This transaction does not require a merkle proof.

  1. Withdraw - Loopring design doc

Forced exit

If the user experiences censorship from the operator with regular exit they can submit their withdrawal requests directly on L1. The system is then obliged to service this request. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular exit.

  1. Forced Request Handling - Loopring design doc
  2. ExchangeV3.sol#L8118 - Loopring source code, forceWithdraw function

Emergency exit

If the 15d deadline passes and the forced exit is still ignored the user can put the system into Withdrawal Mode, disallowing further state updates. In that case everybody can withdraw by submitting a merkle proof of their funds with their L1 transaction.

  1. Forced Request Handling - Loopring design doc
  2. ExchangeV3.sol#L8159 - Loopring source code, withdrawFromMerkleTree function


The system uses the following set of permissioned addresses:

ProxyOwner 0xDd2A…9c97

This address is the owner of the following contracts: LoopringIOExchangeOwner, ExchangeV3 (proxy), BlockVerifier, AgentRegistry, LoopringV3. This allows it to grant access to submitting blocks, arbitrarily change the forced withdrawal fee, change the Verifier address and upgrade ExchangeV3 implementation potentially gaining access to all funds in DefaultDepositContract. This is a Gnosis Safe with 4 / 7 threshold.

Those are the participants of the ProxyOwner.

RollupOwner 0x153C…8512

The rollup owner can submit blocks, set rollup parameters and shutdown the exchange.

Smart contracts

A diagram of the smart contract architecture
A diagram of the smart contract architecture

The system consists of the following smart contracts:

Main Loopring contract.

Can be upgraded by: ProxyOwner

Upgrade delay: No delay

LoopringIOExchangeOwner 0x153C…8512

Contract used by the Prover to submit exchange blocks with zkSNARK proofs that are later processed and verified by the BlockVerifier contract. It allows to give or revoke permissions to submit blocks and to open block submission to everyone.

DefaultDepositContract 0x674b…Bd3f

ERC 20 token basic deposit contract. Handles user deposits and withdrawals. This contract can store any token.

LoopringV3 0xe56D…0C71

Contract managing LRC staking for exchanges (one Loopring contract can manage many exchanges). It also allows to change the forced withdrawal fee and the Verifier address.

BlockVerifier 0x6150…01ef

zkSNARK Verifier based on ethsnarks library.

Can be upgraded by: ProxyOwner

Upgrade delay: No delay

AgentRegistry 0x39B9…ea14

Agent registry that is used by all other Loopring contracts. Currently used are FastWithdrawalAgent, ForcedWithdrawalAgent, DestroyableWalletAgent and a number of LoopringAmmPool contracts.

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).