Arbitrum Nitro: Sneak Preview

Offchain Labs
Offchain Labs
Published in
4 min readOct 11, 2021

tl;dr: Today we’re unveiling Arbitrum Nitro, the next iteration of Arbitrum, which we’ve been working on for months. It’s built on standard technologies like WASM and Geth, so it’s more EVM-compatible, an order-of-magnitude faster than our current tech, and adds another 0. When it’s ready we’ll be deploying it as a seamless upgrade to Arbitrum One.

42. The answer to the Ultimate Question of Life, the Universe, and Everything. But also the number of days since we opened up Arbitrum One. And what an incredible 42 days it’s been! We continue to be overjoyed by the speed at which projects have adopted Arbitrum — including your favorite Ethereum projects and a thriving ecosystem of Arbitrum native dapps. Arbitrum One has facilitated hundreds of project launches, hundreds of thousands of unique user interactions, millions of transactions, and billions of dollars in bridged assets. But as we noted when we launched, this is only the beginning. And today we answer one of the questions we get most often: what’s next?

One of the decisions that we made early on when building Arbitrum was the focus of EVM compatibility and replicating the Ethereum developer experience. Since Arbitrum’s academic origins in 2013, we pioneered interactive fraud proofs, and our design gave us extreme flexibility in designing a Layer 2 platform that was fully compatible with the EVM. About 14 months ago, we began an exploratory research project asking if we could build a version of Arbitrum powered by the popular WebAssembly (WASM) architecture. The potential benefits were clear: a version of Arbitrum that was much faster and also even more compatible with the EVM — because existing EVM engines can run on WASM.

Over time the project has morphed from a one-person research project to a fully staffed production level development effort that’s well underway. And today, for the first time, we’re excited to share what we’ve learned and what’s coming. Buckle up. It’s kind of a big deal.

Arbitrum Nitro: How it works

At the root of the technology is a new prover, which can do Arbitrum’s classic interactive fraud proofs over WASM code. That means the L2 Arbitrum engine can run on WASM, replacing the custom-designed AVM architecture we use today. And because we’re compiling Arbitrum to WASM, the whole system can be built and compiled using standard languages and tooling, replacing the custom-designed language and compiler we use today.

Now here’s the coolest part: we compile the core of Geth, the EVM engine that practically defines the Ethereum standard, right into Arbitrum. So our current custom-built EVM emulator is replaced by Geth, the most popular and well-supported Ethereum client.

The last piece of the stack is a slimmed-down version of our ArbOS component, rewritten in Go, which provides the rest of what’s needed to run an L2 chain: things like cross-chain communication, and a new and improved batching and compression system to minimize your L1 costs.

A Seamless Upgrade

At this point you’re probably asking: what will I need to do to upgrade my apps and assets deployed on Arbitrum One? The answer is: nothing! We’re going to roll this out as a seamless upgrade to Arbitrum One, so there’s no need to migrate anything. Existing dapps will still work, and existing data and events will remain accessible.

Arbitrum is a production system and our commitment to our users is that we will always do our best not to delete any state or restart the chain. One of the defining features of blockchains is that your data will reliably be there, and we take this very seriously and have planned our roadmap ahead of time to ensure that we can introduce upgrades while maintaining an uninterrupted user experience.

In short, Arbitrum One will just keep working, only faster.

How much faster? We’ll need to test it at scale to get a firm benchmark on the performance gain, but we’re estimating a 20–50x increase in Layer 2 execution speed, and we also expect a sizable decrease in costs.

Wen Nitro?

Development is moving rapidly, and major components of the system including the fraud prover are already fully working. We will have more to say about timelines within the next few weeks. As with all of our releases, we will work hard to ensure that the system’s core functionality is complete and mature before we deploy it. We take our responsibility to our users seriously, so we’re not going to push out a less-than-complete system before it’s ready.

The first step in rolling out Nitro will be a standalone testnet, which will be followed by upgrading the existing Arbitrum Rinkeby testnet, and finally we will push Nitro as an upgrade to Arbitrum One. We will continue to have multisig admin keys for some time after the upgrade, but the protocol will be functionally complete at all times, and indeed our fraud prover is already fully operational on the WASM infrastructure and will be live on our upgraded system from Day 1. Arbitrum One will always have fully functioning fraud proofs.

I’m excited! What should I do to prepare?

Well, you should be excited. We’ll be greatly increasing Arbitum’s capacity, reducing costs and providing an even more compatible EVM experience for developers. Any one of those is reason to get excited, but all of them together is 🤯.

But the best part is that other than getting excited, there’s nothing you need to do! Developers can keep on developing on Arbitrum One and users can keep on transacting on Arbitrum One as usual. We’ll just be pushing some really cool updates while you work. So get back to it, and thanks so much for all of your support! 💙



Offchain Labs
Offchain Labs

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