Coinbase’s blockchain got faster. Some apps can still connect but get no data
Base’s Denim upgrade, activated Nov. 5, retired Flashblocks data feeds. Their WebSocket endpoints may still accept connections but no longer provide updates, so apps must migrate to subscriptions through a WebSocket-capable RPC provider or their own node. The pending block tag now returns the latest canonical block, not Flashblocks preconfirmation state, and preconfirmed receipts and transaction results are unavailable. Developers should review pending-state assumptions, subscriptions, and related node settings, then test migrations on Base Sepolia or Vibenet. Base’s upgrade notice reported investigation of transaction-inclusion delays and more empty blocks, with no resolution update as of Nov. 9. The 200ms block cadence does not guarantee next-block inclusion or finality; Base distinguishes canonical block arrival from safe and final status tied to Ethereum.
