BNB Chain, the layer-1 blockchain founded by Binance, has announced the launch of a new layer-2 chain called opBNB. The testnet of opBNB went live on June 19 and aims to improve the security and scalability of the Binance blockchain network.

opBNB is compatible with the Ethereum Virtual Machine (EVM), which means it can run Ethereum-based smart contracts, networks, and ERC-20 tokens. opBNB uses optimistic rollups, a technique that scales transactions by assuming they are valid until proven otherwise. This reduces the load on the root chain and lowers the transaction costs.

According to BNB Chain, opBNB can support more than 4,000 transfer transactions per second and an average transaction cost of less than $0.005. BNB Chain currently claims around 2,000 transactions per second with transaction costs of around $0.10.

opBNB also has some features that differentiate it from Optimism, such as optimizing data accessibility, caching layer, and submission process algorithm. This allows it to increase the gas limit to 100 million per block from the 30 million that Optimism allows.

Binance stated that opBNB is its “answer to the scalability challenge that has limited the mass adoption of blockchain technology.” It also added that opBNB provides a user-friendly interface for developers to integrate their applications without worrying about the complexities of layer-2 scaling.

However, not everyone is convinced by opBNB’s benefits. Adam Cochran, a partner at Cinneamhain Ventures, criticized BNB Chain for centralizing an Ethereum fork and turning up the gas limit to an unsafe level. He also suggested that there were other options for scaling such as joining Optimism as a “superchain,” becoming a layer-2 directly on Ethereum, or even a layer-3 on Optimism or Arbitrum