Base has introduced Flashblocks technology on the testnet, reducing block time to 0.2 seconds, with the mainnet expected to launch in Q2.

Coinbase's Layer 2 chain, Base, has implemented a technology called Flashblocks on its testnet, reducing the effective block time from 2 seconds to 200 milliseconds. Flashblocks is currently available for testing on the Base Sepolia testnet, with plans to transition to the mainnet in the second quarter. This technology achieves faster transaction processing and early confirmation and rollback protection by streaming pre-confirmed blocks every 200 milliseconds. This tenfold speed improvement aims to enhance scalability and usability for developers and users within the Base ecosystem. Flashblocks was developed in collaboration with the research and development team Flashbots, which focuses on Ethereum transaction ordering and MEV solutions. Uniswap has also utilized the same technology to achieve a block time of 0.25 seconds on Layer 2 Unichain. Flashblocks is one of three new tools announced by Base at ETHDenver 2025, with the other two being Base Appchains and smart wallet sub-accounts, both currently in development. Appchains are customizable, application-specific blockchains built on the Base Layer 2 network, which will serve as Layer 3 chains or rollups within rollups, providing dedicated block space to assist applications in scaling. The team also introduced smart wallet sub-accounts, allowing users to manage multiple on-chain wallets from a single interface. Base is an optimistic rollup that processes transactions outside of the Ethereum main blockchain and only periodically publishes transaction data on-chain. It is the Layer 2 chain with the highest daily active users on Ethereum.