Base Switches Off Flashblocks as Denim Goes Live: The Migration Risks Behind 200ms Blocks

Base's Denim upgrade replaced Flashblocks with five canonical blocks per second. What that means for sequencers, RPC providers and smart contract developers is where the real story sits. For about sixteen months, Base's fastest blocks were only promises. Since November 5, they are the ledger itself. Base Swaps Previews for Real Blocks Denim went live on Base mainnet on November 5, after activating on Sepolia on October 21. According to the upgrade page , the chain now produces five complete canonical blocks every second instead of one every two seconds.