Arbitrum Stylus could cut costs 100x with two virtual machines

Offchain Labs, the team behind Ethereum layer-2 scaling network Arbitrum, has launched the testnet for Arbitrum Stylus, a new programming environment that enables developers to write smart contracts in Rust, C, and C++.

The primary coding language for Ethereum smart contracts today is Solidity. 

With Arbitrum Stylus, developers can now use familiar programming languages to build on Arbitrum, Rachel Bousfield, tech lead at Offchain Labs, told Blockworks.

“If someone out there is working in Rust, or C or C++, instead of having to learn a new programming language like Solidity or Vyper, they can just use technologies they are already familiar with and write their applications and make their products in those,” Bousfield said.

If the Arbitrum DAO chooses to adopt Stylus, the tool will be available for developers on Arbitrum One, Arbitrum Nova and Arbitrum Orbit. A date for a vote has not been set, and indications are that the plan is to gather testnet feedback before submitting a proposal. 

According to a Statista report, which surveyed 87,585 software developers, only 1.33% of respondents said they used Solidity. By comparison, 19.34% and 22.42% of respondents used C and C++, respectively, and 13.05% used Rust.  

The Stylus’ developer-friendly technology is enabled through Arbitrum Nitro, a significant tech stack upgrade to Arbitrum One that occurred in 2022. 

All fraud proofs on Arbitrum Nitro currently use the third-party open sourced software WebAssembly (Wasm), which can prove the incorrectness of arbitrary programs, Bousfield said. Wasm is today supported by nearly all web browsers, as well as programming languages, that underpin the internet. 

“What we’ve done is made it such that arbitrary programs that are untrusted can now be proven as well,” she said. “So, using that same Wasm fraud prover, with some minor modifications that don’t change the actual trust or safety of Arbitrum, we’re able to add new kinds of Wasms which include people writing their programs in Rust, C or C++.”

Interoperable coding languages

To ensure optimal performance, coding languages on Stylus will be completely interoperable, Bousfield said. 

To accomplish that, different coding languages will work in tandem. For example, if a developer is programming in Rust, they are able to import a Solidity interface or vice versa.

This is possible because Solidity contracts have a way to call each other. 

“Since everything expects to be called and call each other in the same way, it doesn’t matter what the implementation details are of the contract you’re interfacing with,” Bousfield said. 

Existing Solidity DEXes will be able to list — without any modifications — ERC-20 tokens written in Rust, for example, and those programs may call out to C programs to do cryptography.

“We don’t have to go to all these different DEXs and say, ‘Please update your code so they can have Rust tokens, the Rust tokens’ — from their perspective —  just looks like Solidity tokens, so the DEXs won’t know the difference,” Bousfield said.

Slashing fees

Beyond lowering barriers of entry, Stylus will also reduce fees. 

“For the same amount of cost it takes to do an ADD instruction in Solidity, you can execute 150 ADD instructions in Stylus,” Bousfield said. “For compute intensive work, Stylus probably cuts costs somewhere between 10, 50 or 100x, just depends very greatly on what you’re doing.”

This is because, rather than having one virtual machine, Stylus will have two virtual machines. One will be the unmodified Ethereum Virtual Machine for developers who write using a Solidity contract, then a separate Wasm virtual machine.

Source: Offchain Labs

Wasm is a standard for many companies like Google, Apple or Microsoft. 

“Web browsers use [Wasm] to generate pages. It needs to be fast, and due to all the industry support, the runtimes that actually perform Wasm execution are just way faster than that of the Ethereum virtual machine,” Bousfield said.

Another reason why Stylus will be cheaper: Developers will be able to use standard tooling for C, C++ and Rust, which produce better bytecodes than Solidity.

“They use techniques like LLVM, which have been worked on for over 50 years, there’s decades of work that has been put into making C, and now you get to inherit all of that research, development and optimizations in your code,”  Bousfield said. 

Next steps

Audits for Arbitrum Stylus testnet is underway, and the team at Offchain Labs is looking to hear back from community members following its testnet launch.

The team is also looking to add more programming languages to Stylus, and further finding ways to reduce fees.

“It’s a constant race to improving the performance of layer-2, and this is just one step in that,” Bousfield said.

Updated Aug 31, 2023 at 9:45 am ET: Added additional context.

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