Protocols. Flashblocks on Optimism is live on every Chainstack Optimism mainnet node. The Optimism sequencer streams Flashblocks every 250ms, and Chainstack Optimism nodes expose the preconfirmation state through standard JSON-RPC calls with the pending block tag — eth_getBlockByNumber, eth_call, eth_getBalance, eth_getTransactionCount, eth_getCode, eth_getStorageAt, eth_estimateGas — plus eth_getTransactionReceipt, eth_getTransactionByHash, and eth_sendRawTransactionSync for preconfirmed transactions.
See Flashblocks on Optimism for the full guide, including the Optimism vs. Base differences, performance expectations, and a verification snippet. Last modified on May 18, 2026
