Polygon zkEVM Interview

For anyone not familiar, what is Polygon's zkEVM?

Polygon zkEVM is the first zero-knowledge scaling solution that's fully equivalent to EVM: All existing smart contracts developer tools and wallets work seamlessly. The zkEVM harnesses the power of ZK proofs to reduce transaction cost and massively increase throughput, all while inheriting the security of Ethereum L1.

How do zk-rollups work?

Zk roll-ups aggregate a large batch of transactions and proves all of them to the Ethereum network with a single ZK validity proof.

How scalable will zkEVM be?

We're still doing testing, so no specifics yet, but it will be more scalable than layer 1 Ethereum. Users will see increased scalability using this solution.

What kind of fee reduction can users expect?

Compared to Ethereum Layer 1 users can expect a significant reduction in gas fees. Our layer 2 scaling solution batches transactions together and then effectively spreads the cost of a single layer 1 transaction across multiple layer 2 transactions.

Can you talk about Ethereum Virtual Machine compatibility and why this is so important?

Our ultimate goal is not compatibility. Our ultimate goal is equivalence. Solutions that are compatible enable most of the existing apps to work, but sometimes with code changes. Additionally, compatibility may lead to the breaking of developer tooling. We strive for EVM Equivalence because it means that applications, tools, and infrastructure built on Ethereum can immediately port over to zkEVM with zero changes needed. Everything will work 100% on day one. This is important, because:

1. Development teams don't have to make changes to their code, which could add a security vulnerability.
2. Since no code changes are needed neither are additional audits, which saves teams money.
3. The experience for a developer is much better. Since he/she is not rewriting the application value time is saved.
4. Our solution ultimately benefits from the security and decentralization of Ethereum, since we're still finalizing everything on Ethereum.
5. Allows zkEVM to benefit from the already vibrant and active Ethereum community.
6. Allows for significant and quick Dapp adoption, since all apps built on Ethereum today are 100% compatible

Can this layer two work with other chains?

Aspirationally, the goal in the future is to build one of many chains that allow for users' assets to move from layer 2 (L2) to layer 2. With that being said, users will not be able to utilize this functionality at launch, but L2 to L2 movement is something we have road mapped for the future.

What is your plan to gain market share from the likes of Arbitrum and Optimism?

When evaluating ZK rollups versus Optimistic Rollups like Arbitrum and Optimism if a user chooses the ZK rollup it's most likely because they're prioritizing finality and capital efficiency.

When can we expect the testnet and mainnet?

Testnet late 2022, Mainnet Early 2023