Base Denim Upgrade Targets 200-Millisecond Blocks for November Mainnet
Base Cuts Block Time to 200 Milliseconds Base, the Coinbase-incubated Layer-2 network, is preparing to cut its official block interval from two seconds to 200 milliseconds under the Denim upgrade, with mainnet activation targeted for November 2026. The upgrade is already live on the Base Sepolia testnet, where the networks official status page records it as applied since October 21. Upgrade documentation lists mainnet status as planned, with no fixed activation date. Today Base produces one official block every two seconds, 43,200 per day. Under Denim, output moves to one block every 200 milliseconds, five per second, lifting daily production to 432,000. The jump is a change in block count, not a guaranteed tenfold rise in transaction throughput, and the effect on fees and user costs cannot be derived from the interval alone. Base has long supplied preconfirmations through Flashblocks, preliminary signals issued roughly every 200 milliseconds before an official block lands. Denim changes that arrangement: rather than shortening the preconfirmation cycle, it creates numbered, recorded blocks at the same cadence, so applications must distinguish fast preliminary signals from blocks written to the chain. The upgrade documentation sets out operator impact in detail. Apps that subscribe to Flashblock data or query
