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Layer 2

Ethereum for everyone

Scaling Ethereum for mass adoption.

What is layer 2?

Layer 2 (L2) is a collective term to describe a specific set of Ethereum scaling solutions. A layer 2 is a separate that extends Ethereum and inherits the security guarantees of Ethereum.

Now let’s dig into it a bit more. To do this we first need to explain layer 1 (L1).

What is layer 1?

Layer 1 is the base blockchain. Ethereum and Bitcoin are both layer 1 blockchains because they are the underlying foundation that various layer 2 networks build on top of. Examples of layer 2 projects include "rollups" on Ethereum and the Lightning Network on Bitcoin. All user transaction activity on these layer 2 projects can ultimately settle back to the layer 1 blockchain.

Ethereum also functions as a layer for layer 2s. Layer 2 projects will post their transaction data onto Ethereum, relying on Ethereum for data availability. This data can be used to get the state of the layer 2, or to dispute transactions on layer 2.

Ethereum as the layer 1 includes:

  1. A network of node operators to secure and the network

  2. A network of block producers

  3. The blockchain itself and the history of transaction data

  4. The for the network

Still confused on Ethereum? Learn what Ethereum is.

Why do we need layer 2?

Three desirable properties of a blockchain are that it is decentralized, secure, and scalable. The blockchain trilemma(opens in a new tab) states that a simple blockchain architecture can only achieve two out of three. Want a secure and decentralized blockchain? You need to sacrifice scalability.

Ethereum currently processes 1+ million transactions per day. The demand to use Ethereum can cause transaction fee prices to be high. This is where layer 2 networks come in.

Scalability

The main goal of layer 2 is to increase transaction throughput (higher transactions per second) without sacrificing decentralization or security.

Ethereum (layer 1) is only able to process roughly 15 transactions per second. When demand to use Ethereum is high, the network becomes congested, which increases transaction fees and prices out users who cannot afford those fees. Layer 2s are solutions that reduce those fees by processing transactions off the layer-1 blockchain.

More on Ethereum's vision

Benefits of layer 2

Lower fees

By combining multiple off-chain transactions into a single layer 1 transaction, transaction fees are massively reduced, making Ethereum more accessible for all.

Maintain security

Layer 2 blockchains settle their transactions on Ethereum Mainnet, allowing users to benefit from the security of the Ethereum network.

Expand use cases

With higher transactions per second, lower fees, and new technology, projects will expand into new applications with improved user experience.

How does layer 2 work?

As we mentioned above, layer 2 is a collective term for Ethereum scaling solutions that handle transactions off Ethereum layer 1 while still taking advantage of the robust decentralized security of Ethereum layer 1. A layer 2 is a separate blockchain that extends Ethereum. How does that work?

There are several different types of layer 2, each having their own trade-offs and security models. Layer 2s take the transactional burden away from the layer 1 allowing it to become less congested, and everything becomes more scalable.

Rollups

Rollups bundle (or ’roll up’) hundreds of transactions into a single transaction on layer 1. This distributes the L1 transaction fees across everyone in the rollup, making it cheaper for each user.

The transaction data in the rollup is submitted to layer 1, but the execution is done separately by the rollup. By submitting transaction data onto layer 1, rollups inherit the security of Ethereum. This is because once the data is uploaded to layer 1, reverting a rollup transaction requires reverting Ethereum. There are two different approaches to rollups: optimistic and zero-knowledge - they differ primarily on how this transaction data is submitted to L1.

Optimistic rollups

Optimistic rollups are 'optimistic' in the sense that transactions are assumed to be valid, but can be challenged if necessary. If an invalid transaction is suspected, a fault proof is run to see if this has taken place.

More on optimistic rollups

Zero-knowledge rollups

Zero-knowledge rollups use validity proofs where transactions are computed off-chain, and then compressed data is supplied to Ethereum Mainnet as a proof of their validity.

More on ZK-rollups

Do your own research: risks of layer 2

Many layer 2 projects are relatively young and still require users to trust some operators to be honest as they work to decentralize their networks. Always do your own research to decide if you're comfortable with any risks involved.

For more information on the technology, risks, and of layer 2s, we recommend checking out L2BEAT, which provides a comprehensive risk assessment framework of each project.

Go to L2BEAT(opens in a new tab)

Use layer 2

Now that you understand why layer 2 exists and how it works, let's get you up and running!

If you are using wallet such as Safe or Argent, you will not have control over this address on a layer 2 until you redeploy your contract account to that address on the layer 2. Classic accounts with will automatically own the same account on all layer 2 networks.

Generalized layer 2s

Generalized layer 2s behave just like Ethereum — but cheaper. Anything that you can do on Ethereum layer 1, you can also do on layer 2. Many have already begun to migrate to these networks or have skipped Mainnet altogether to build projects straight on a layer 2.

Arbitrum One

universal

Arbitrum One is an Optimistic Rollup that aims to feel exactly like interacting with Ethereum, but with transactions costing a fraction of what they do on L1.

Note: Fraud proofs only for whitelisted users, whitelist not open yet

Arbitrum One Bridge(opens in a new tab)Arbitrum One Ecosystem Portal(opens in a new tab)Arbitrum One Token Lists(opens in a new tab)
Explore Arbitrum One(opens in a new tab)

Optimism

universal

Optimism is a fast, simple, and secure EVM-equivalent optimistic rollup. It scales Ethereum's tech while also scaling its values through retroactive public goods funding.

Note: Fault proofs in development

Optimism Bridge(opens in a new tab)Optimism Ecosystem Portal(opens in a new tab)Optimism Token Lists(opens in a new tab)
Explore Optimism(opens in a new tab)

Boba Network

universal

Boba is an Optimistic Rollup originally forked from Optimism which is a scaling solution that aims to reduce gas fees, improve transaction throughput, and extend the capabilities of smart contracts.

Note: State validation in development

Boba Network Bridge(opens in a new tab)
Explore Boba Network(opens in a new tab)

Base

universal

Base is a secure, low-cost, developer-friendly Ethereum L2 built to bring the next billion users to web3. It is an Ethereum L2, incubated by Coinbase and built on the open-source OP Stack.

Note: Fraud proof system is currently under development

Base Bridge(opens in a new tab)Base Ecosystem Portal(opens in a new tab)
Explore Base(opens in a new tab)

ZKsync

universal

ZKsync is a ZK Rollup that aims to scale Ethereum and its values to mainstream adoption, without degrading security or decentralization.

ZKsync Bridge(opens in a new tab)ZKsync Ecosystem Portal(opens in a new tab)ZKsync Token Lists(opens in a new tab)
Explore ZKsync(opens in a new tab)

Starknet

universal

Starknet is a Validity Rollup Layer 2. It provides high throughput, low gas costs, and retains Ethereum Layer 1 levels of security.

Starknet Bridge(opens in a new tab)Starknet Ecosystem Portal(opens in a new tab)Starknet Token Lists(opens in a new tab)
Explore Starknet(opens in a new tab)

Application specific layer 2s

Application specific layer 2s are projects that specialize in optimizing for a specific application space, bringing improved performance.

Loopring

paymentsexchange

Loopring's zkRollup 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.

Loopring Bridge(opens in a new tab)
Explore Loopring(opens in a new tab)

ZKSpace

paymentsexchange

The ZKSpace platform consists of three main parts: a layer 2 AMM DEX utilizing ZK-Rollups technology called ZKSwap, a payment service called ZKSquare, and an NFT marketplace called ZKSea.

ZKSpace Bridge(opens in a new tab)
Explore ZKSpace(opens in a new tab)

Aztec

paymentsintegrations

Aztec Network is the first private zk-rollup on Ethereum, enabling decentralized applications to access privacy and scale.

Aztec Bridge(opens in a new tab)
Explore Aztec(opens in a new tab)

A note on sidechains, validiums, and alternative blockchains

Sidechains and validiums are blockchains that allow assets from Ethereum to be bridged over and used on another blockchain. Sidechains and validiums run in parallel with Ethereum, and interact with Ethereum through , but they do not derive their security or data availability from Ethereum.

Both scale similarly to layer 2s - they offer lower transaction fees and higher transaction throughput - but have different trust assumptions.

Some layer 1 blockchains report higher throughput and lower transaction fees than Ethereum, but generally with trade-offs elsewhere, for example greater hardware requirements for running nodes.

How to get onto a layer 2

There are two primary ways to get your assets onto a layer 2: bridge funds from Ethereum via a smart contract or withdraw your funds on an exchange directly onto the layer 2 network.

Funds in your wallet?

If you've already got your ETH in your wallet, you'll need to use a bridge to move it from Ethereum Mainnet to a layer 2.

More on bridges

Select L2 you want to bridge to

Funds on an exchange?

Some centralized exchanges now offer direct withdrawals and deposits to layer 2s. Check which exchanges support layer 2 withdrawals and which layer 2s they support.

You'll also need a wallet to withdraw your funds to. Find an Ethereum wallet.

Select...
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Tools to be effective on layer 2

Information

  • L2BEAT
    L2BEAT
    L2BEAT is a great resource for looking at technical risk assessments of layer 2 projects. We recommend checking out their resources when researching specific layer 2 projects.
    Goto L2BEAT website(opens in a new tab)
  • Ethereum Ecosystem
    Ethereum Ecosystem
    Unofficial Ecosystem page of Ethereum and its Layer 2s including Base, Optimism, and Starknet featuring hundreds of dApps and tools.
    Goto Ethereum Ecosystem website(opens in a new tab)
  • growthepie
    growthepie
    Curated analytics about Ethereum layer 2s
    Goto growthepie website(opens in a new tab)
  • L2 Fees
    L2 Fees
    L2 Fees lets you see the current cost (denominated in USD) for doing transactions on different layer 2s.
    Goto L2 Fees website(opens in a new tab)
  • Chainlist
    Chainlist
    Chainlist is a great resource for importing network RPC's into supporting wallets. You will find RPC's for layer 2 projects here to help get you connected.
    Goto Chainlist website(opens in a new tab)

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