TraceHawk now supports detailed output roots tracking for optimistic rollup Layer2s. By introducing future-aligned features like stage-1 decentralization, native interoperability, untapped liquidity access, and even creation of ZK-powered L2s, the optimistic rollups stack has already been identified as the most matured and widely adopted across web3 builders. As per L2beat’s, 41 chains have been launched, where Arbitrum One ($16.10B TVL), Base ($13.68B TVL)), and OP Mainnet ($6.22B TVL)are the biggest players.

Optimistic rollup Layer2s building with any stack– OP Stack or Arbitrum Orbit can use TraceHawk as their custom block explorer to allow efficient tracking of L2 output roots in a zero-hassle way. Let’s dive in and understand more about output roots, along with a step-by-step process of tracking them on Zeeve’s TraceHawk. 

Understanding Output Roots in Layer2s

Output roots are cryptographic on-chain data that represent a Layer2’s commitment to its data or transactions. This means that output roots provide a comprehensive list of output data occurring from operations or transactions in a Layer2 chain. 

In a optimistic rollup setup, transactions are processed off-chain (on a separate layer). However, upon processing of each block, the corresponding output needs to be synched properly with the Layer1 (settlement layer). This ensures trustless execution of Layer2–Layer1 interactions, for example- withdrawals. 

‘Proposers’ are the authorized entity to submit L2 output roots on Layer1. However, this submission can be challenged through a fault proof system. Note that the fault proofs has been implemented through the Cannon upgrade. In case a Optimistic rollup chain is not optimized with the Cannon, it has still accept challenges against output roots by integrating output-root challenger into the network’s nodes. 

Integrated output root in your L2 with TraceHawk. Stay ahead by ensuring smooth and secure tracking for each interactions. Learn more! 

How output root work in Layer2s?

On a basic level, output roots works like this:

• Withdrawals are initialized in Layer2 rollup.
• Proposers submits output roots to L1. 
• A waiting period will be there to identify incorrect roots.
• Transactions are finalized after the withdrawal period is over. 

For a high-level overview, let’s discuss the multiple components of a L2 rollup protocol, see their contribution in transaction processing, and thus understand output root execution. Let’s understand this whole process from the perspective of OP stack rollups. Below are permissioned components in a OP rollup, which also include proposer that is accountable for output roots submission. 

• Op-geth- the component to implement L2 execution layer, ensuring a 100% secure environment for  Ethereum-equivalent environment.
• Op-batcher- the component responsible for submitting Layer2 sequencer’s data to settlement Layer (L1), making it all available to the verifiers.
• Op-deployer- the tool for adding abstraction layer to OP Stack chain deployment that are uses wide contract from Superchain. 
• Op-proposer- the component for submitting L2 output roots to the Layer1. 

Here’s a graphical overview of how these components works together, enabling smooth output root execution in a L2 OP rollup: 

Source: Optimism

Why it is important to track output roots?

Tracking output roots in Layer2s is equally important for entities, including L1 sequncers, node participants, light clients, or community & developers. Here’s why:

• Security: With L2 output roots, the underlying L1 can easily verify the auethenticiy of L2 state without needing to interact or process individual L2 transactions. However, through fault-proofs, the chain allows anyone to challenges the output roots of they believes it’s not correct. 

• Validity proof:  In case of dispute or audit disagreements, output roots allows for verification of off-chain transactions. Validators or 3rd party auditors can access the data and validate it. And, since L2 output roots are derived from Merkle trees ( built upon cryptographic hashes), these are temper-proof, which eliminates chances of manipulations.

• Trustless Verification: Using output roots, light clients (users with limited resources) can trustlessly verify claims about the L2 state like withdrawals, without relying on any central authority.

• Cross-Chain Interaction: When interacting with Layer 1 chains or a external systems, L2 output roots summarize and transfer the state of L2 chains to these systems, making it easier to maintain consistency in cross-chain communication. 

Curious about how this will work on your L2? Connect with our experts and get hands-on information. 

Track L2 output roots quickly with Zeeve’s TraceHawk– Block explorer for rollups and appchains

Desiged as the specialized block explorer for appchains and rollups– Zeeve’s TraceHawk has simplified output root tracking for optimistic rollup L2s. Here’s the step-by-step process. All these operations have been perfomed on a custom OP Stack rollup– The Binary Holdings. 

1. Visit TraceHawk. Click ‘connect wallet’ positioned in the top-right corner. Connect your Metamask by accepting the connection request on your wallet’s interface.

2. Once wallet is connected, click on the ‘Blockchain’ from the menu bar and again click on ‘Output roots’. 

3. This action will open a separate dashboard showing the detailed information about L2 output roots. As you can see in the below image, there is L2 output index, output root’s age, L2 block number, L1 transaction hash, and output address. From here, you can see the output root details and use them for specific purposes, such as transaction validation, security usage, or even for challenging them. 

4. Additionally, if you want to dive deeper into L1 transaction hash, click on the hash and it will show you end-to-end details about the transaction, including transaction overview, internal transactions, logs, and state. 

5. Similar to output roots, you can use TraceHawk explorer to seamlessly track data about transactions, deposits, withdrawals, blocks, transaction batches, dispute games, and verified smart contracts. 

Explore TraceHawk’s capabilities and features from this article: TraceHawk: A Full-suite Multi-ecosystem Block Explorer

Need your custom block explorer? Try Zeeve’s TraceHawk!

If you’re building a L2 chain, having a custom block explorer is great for improved user experience and enhanced network functionality. Don’t build from scratch! TraceHawk from Zeeve offers a quick and cost-efficient way to customize an explorer to your L2’s specific needs.

Want to track Layer3 activity? Need specific UX tweaks or advanced filters? TraceHawk lets you customize the explorer to match your vision. It’s perfect for Arbitrum Orbit, ZK Stack chains, Polygon CDK, Parachains, and all leading rollups and appchains.

TraceHawk  is suitable for Arbitrum Orbit, ZK Stack chains, Polygon CDK, Parachains, and all the leading rollups & appchains. For more information about TraceHawk’s features, customization, and offerings, connect with our experts. Or, try TraceHawk yourself.