I started this series with a focus on all types of scalability enhancements, but there’s so much happening I’m unable to keep up. So, I’ve decided to focus my limited bandwidth on the best solution: rollups + data shards. Even then, I’m sure I’ve missed some things, so feel free to add in the comments below! I’m assuming you’re familiar with these rollup chains, if not please see here for a brief overview about them.
Arbitrum One
Arbitrum One (A1) has been live on mainnet since 28th May, but with a whitelist for using the chain. Currently, developers are invited to deploy their smart contracts. Over 600 contracts have been deployed, including top DeFi apps like Uniswap V3 and Sushi. Personally, I had expected A1 to be opened to everyone by early July, but it seems like Offchain Labs are waiting for some final pieces of the infra to come together. One such element could be Etherscan, who are scheduled to release Etherscan for A1 end of July. I’d expect A1’s whitelists to be lifted in the coming weeks.
This just in: Reddit will scale with Arbitrum! (But not A1, they’ll deploy their own chain.)
Optimistic Ethereum
Optimistic Ethereum (OE) has taken a similar but different approach — anyone can use the chain, but there’s a whitelist for contract deployment. The first contract deployed was, of course, Synthetix staking way back in January 2021. Uniswap V3 was the next, earlier this month. Currently, there are only 6 or 7 tokens that you can transfer or swap on Uniswap. We’ll see Chainlink and most of Synthetix’s ecosystem deployed next week. Following that, the Optimism team will still maintain a whitelist for contract deployment, but are committed to taking a liberal approach where all projects successfully deployed to testnet will be let in. I imagine Chainlink was a key dependency for multiple projects, and we’ll see many more deployed after that. OE is committed to the sequencer auction model for decentralizing sequencers, with the proceeds going to public goods funding.
zkSync 2.0
zkSync 2.0 has been live in private testnet since the end of May. The current hold up to making this public is the compiler, but as of 21st July it’s coming soon. While the initial optimistic target for mainnet was August, I’d say Q4 is the most likely launch timeframe, but we’ll have clearer idea when the public testnet is live. zkPorter was initially expected to release 2 months after the rollup, and decentralized sequencers after that, though it’s unclear where the schedules currently lie. I’d presume we’ll find out when the testnet finally goes public.
Some additional information not covered in the Big Four post: zkSync 2.0 will implement timelocks to mitigate MEV. zkSync’s token will be released some time before zkSync 2.0’s mainnet genesis, alongside a liquidity mining program of some sort. There’ll be no whitelists on the testnets or mainnets, unlike A1 and OE — it’ll be open to all.
StarkNet
StarkNet Planets Alpha 1 is now live on public testnet. Currently, anyone can deploy Cairo smart contracts to the testnet. The final missing piece is composability between smart contracts. Following that, we should expect the StarkNet Constellations release late this year. This is when StarkNet is open to all. The final phase, Universe, is on track for early 2022, bringing decentralized sequencers and provers.
StarkNet is collaborating with Nethermind to build Warp, a EVM > Cairo compiler, that closes StarkNet’s greatest weakness! Details are scarce currently, so it’s unknown how close they’ll get to zkSync’s solution, but it does seem like you’ll be able to deploy most Solidity or Vyper contracts to StarkNet. Also, the Erigon (TurboGeth) team is building StarkNet’s full node client. It’s great to see the best of the Ethereum ecosystem come together!
Hermez
Welcome to the newest programmable zkR! Like zkSync 1.x, Hermez is currently a payments-only zkR. Unlike zkSync 2.0 and StarkNet, Hermez is actually replicating the EVM 1:1 with the full set of EVM opcodes supported! It’ll decentralized sequencers using an auction mechanism, like OE. Testnet is currently planned for Q4 2021, with a mainnet release in Q2 2022. Interestingly, this is the first network on this list with a token, since people often complain they can’t find ways to invest.
Some other programmable rollups: OMGX, which is an OE fork, continues to be live on testnet. Fuel, an optimistic rollup, is taking a novel approach with UTXO model. Cartesi is continuing to roll out their optimistic rollup on testnet. No news from Polygon, but presumably they are building both optimistic and zk rollups. They announced Avail, a data availability chain. Along with Celestia, these will be interesting solutions to watch for the validium space. As for application-specific validiums: Immutable X is close to opening to developers, with top projects like OpenSea and Mintable expected to release. Sorare released their validium solution yesterday — enabling enough scalability to onboard the entire world of fantasy football onto Ethereum. Finally, there are multiple talks about cross-L2 interoperability and composability at EthCC — this is certainly an area multiple developers are tackling.
