Hi! We are glad you've made it here. Below you will find answers to most frequently asked questions about L2BEAT.

What is the overall purpose of this site?

L2BEAT was created to provide transparent and verifiable insights into emerging layer two (L2) technologies which, in line with the rollup-centric Ethereum scaling roadmap are aimed at scaling Ethereum.

Why do you need L2BEAT if you have DeFi Pulse, DefiLlama, etc.?

While the above-mentioned sites are great, they focus primarily at tracking TVL (Total Value Locked) in DeFi projects on various chain. In comparison L2BEAT will track only L2 projects (at first on Ethereum only) and will eventually report not just TVL but various metrics related to the liveness and security of these projects.

Why does the Total Value Locked (TVL) on L2BEAT differ from the one on DefiLlama?

L2BEAT and DefiLlama use different methodologies for calculating TVL. The TVL on L2BEAT is a sum of canonically bridged, externally bridged, and natively minted assets (e.g. L2-native governance tokens like ARB and OP), while DefiLlama focuses on assets actively engaged in dApps on specific networks.

Example: let’s assume L2BEAT reports a TVL of 2.5 billion, while DefiLlama reports a TVL of 1 billion for the same Layer 2 network (e.g., Arbitrum). This suggests that 1.5 billion worth of assets have been bridged (canonically or externally) or natively minted on Arbitrum, but are not yet being used in any dApps listed by DefiLlama. For instance, if you deposit 1 ETH to Optimism, L2BEAT would include it in their TVL calculation, but DefiLlama would not. However, if you use that 1 ETH on Optimism to provide liquidity on Uniswap, DefiLlama would then include it in their TVL calculation.

The discrepancy in reported TVL between L2BEAT and DefiLlama is due to different interpretations of “Total Value Locked.” L2BEAT considers the entire Ethereum ecosystem, while DefiLlama emphasizes assets used in dApps on individual blockchain networks.

What exactly are L2s and why Polygon is not included?

Trust-minimized L2s are chains that can be exited by interacting directly with L1 alone, eliminating the need to rely on L2 operators for the security of the funds.

In the case of Polygon, an additional layer of trust is introduced: users must trust the majority of Polygon’s validators to enable secure withdrawals and prevent fund theft. Note that application-specific logic, like in the case of dYdX forced trade requests, may also require inter-user dependencies to successfully exit the system.

Why does the main table contain projects that are not trust-minimized L2s yet?

We want to track the progress of the projects that are credibly committed towards becoming trust-minimized L2s. Our goal is to provide the community with the most up-to-date information about the state of these projects and to provide insights and guidance for them to become fully trust minimized.

Are Validiums and Optimiums L2s?

Validiums and Optimiums are not L2s: by not publishing data on L1 they introduce additional trust assumptions on top of it. If the data to reconstruct the state is not made available by the operators of the offchain DA solution, funds are at risk.

If Validiums and Optimiums are not L2s, why are they included?

We include Validiums and Optimiums along with L2s mainly for historical reasons. We introduced them when the L2 space was still in its infancy and we wanted to provide a comprehensive overview of the space. We will continue to track these projects to provide the community with a broader perspective on the state of the space and to provide tools to evaluate the different tradeoffs between the various solutions.

How do L2s derive their security from L1?

There are two primary (and somewhat independent) mechanisms that L2 chains use.

First, the L2 state can be verified by L1 through either Validity Proof or Fraud Proof . This mechanism is most important as it ensures that L2 proposers cannot cheat and include invalid transactions in an L2 block, e.g. mint coins out of thin air or steal your coins.

The second use of L1 is as a Data Availability layer for L2 transactions so that users can independently re-create the L2 state and ensure continued and safe system operation or trustlessly exit to L1.

Can you explain how L1 can help with L2 state validation?

An L2 chain can periodically “commit” its state to L1 by submitting the hash of its current state root. A state root is just a number, e.g: 0x77905a71f4b32221… . We need a mechanism to ensure that this number corresponds to the actual L2 state.

One way to do so is by providing a cryptographic Validity Proof (zkProof) that will be verified by the L1 smart contract. If the verification passes, users can be sure that the state root represents the results of valid transaction execution.

Alternatively, an honest L2 chain observer can challenge roots. They can do this by producing a Fraud Proof. This proof empowers the L1 contract to autonomously confirm the inaccuracy of the state root and subsequently reject it.

What if an L2 proposer submits a fraudulent state commit to L1?

A state root from L2 is typically used to check coin ownership on L2 that user wants to withdraw to L1. If the fraudulent state root is submitted, it may attest that all coins belong to a dishonest L2 validator rather than legitimate users. These coins can be then withdrawn to L1 from L2—effectively stealing them. This is why it is not enough to simply commit state roots of L2 to L1, we need to be sure that this state root is valid.

Are there any other ways L2 validators can steal user's coins?

Most L2 constructions are upgradable and until upgradability mechanism is either fully disabled or controlled by a sufficiently decentralised DAO, the funds can be, in theory, stolen through the upgrade mechanism. L2BEAT will closely monitor how the particular construction is upgradable and who currently controls the upgradability keys.

What about data availability? Why is it important?

To trustlessly withdraw coins from L2, users need to prove ownership of the coins to L1 smart contract that holds all the funds. For that they need to have access to all L2’s transactions or its current state. To not introduce any additional trust assumptions, L2 transactions can simply be recorded on L1 (as cheap calldata).

For more details on data availability and its importance in security of scaling protocols, see Ethereum.org’s page on the topic.

Ok, so what are the main categories of L2s?

We currently acknowledge the following possible designs of trust-minimized L2s:

  • zkRollup - they publish data on L1 (Ethereum) to inherit data availability and consensus guarantees, and use validity proofs to guarantee state roots correctness.

  • Optimistic Rollup - they publish data on L1 to inherit data availability and consensus guarantees, and use fraud proofs to guarantee state roots correctness.

  • State channel - they don’t publish data onchain, but require users to keep their data in order to exit. They’re not general and require users participation.

  • Plasma - they don’t publish data onchain and use fraud proofs for disputes. Similarly to state channels, users are required to keep their data to correctly exit. They don’t require users participation, but they do not support general computation.

By introducing more trust assumptions we can also specify the following categories that fall outside of the L2 boundary:

  • Validium - Those systems rely on validity proofs and data published externally.

  • Optimium - historically named Optimistic Chain. Those systems rely on fraud proofs and data published externally.

For more details see the Incomplete guide to Rollups by Vitalik Buterin.

What happened to Optimistic Chains?

They got renamed to Optimiums for clarity.

How exactly do you calculate metrics like TVL?

It varies from project to project but in general, the TVL is defined as the sum of canonically bridged, externally bridged, and native assets of a given L2. Depending on the token type we might apply a different formula to count the value of this particular token:

  • Canonically bridged token: tokens_locked_on_L1 * price

  • Externally bridged token: total_supply_on_L2 * price

  • Omnichain native token: total_supply_on_L2 * price

  • Regular native token: circulating_supply * price

Please note that in some cases formula might actually be different (for example we may use circulating supply instead of total supply for some tokens)

What do the values in the TVL breakdown mean?
  • Canonically Bridged Value (CBV) is the value of assets that useL1 Ethereum as their main ledger and are bridged to L2 via a canonical bridge locking tokens in L1 escrow and minting on L2 an IOU representation of that token.

  • Externally Bridged Value (EBV) is the value of assets that use some external blockchain as their main ledger and are bridged to L2 via a non-canonical bridge. Tokens are locked on their native ledger and the bridge is minting on L2 an IOU representation of that token.

  • Natively Minted Value (NMV) is the value of assets that use an L2 as their ledger and are minted directly on the L2. Note that for some tokens (omnichain tokens) their ledger is distributed across many blockchains and they can be moved to L2 via a burn-mint bridge.

For more information read the L2 Assets blog post.

Apart from TVL, what is L2BEAT aiming to track?

We will continuously monitor different L2 technologies with the primary focus on user funds’ security. To this end we will track not just the usage of a particular L2 (TVL, frequency of state root commits, number of transactions, gas cost, etc…) but we will try to highlight the main risks related to their implementation that may affect user’s funds security.

Is L2BEAT performing a security audit for each L2?

No, the L2BEAT team DOES NOT DO SECURITY AUDIT. All the information that we present on our site should be independently verified by anyone wanting to use given L2. Our goal is to collect as much information as we can about the “state of L2s” and allow the community to better understand what security assumptions are used to build given L2 solutions.

Why aren't state channel based solutions like Raiden or Nahmii included?

We are currently focused mainly on rollups, but would love to expand our research to state channels in the future. For the time being we lack resources to properly evaluate those systems.

Nahmii was actually listed on L2BEAT for a time, but was removed for the reason stated above. If you want to check TVL for Nahmii you can do that on etherscan.

How can I add a new project or improve some info?

Everything is open source – just create a PR. If you want to add a new project you should read our contributing guidelines.

🔍 Here is also a visual step-by-step guide for creating a Pull Request - link