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Unichain Flashblocks Overview

Updated on
Aug 31, 2026

Overview​

Flashblocks is a transaction preconfirmation feature on Unichain that delivers partial block updates every 200 milliseconds, achieving up to 10x faster confirmations than Unichain's standard 2-second block time. This enables applications to access near-instant transaction feedback, enhancing responsiveness for time-critical use cases like decentralized exchanges and onchain gaming.

Flashblocks is useful for:


  • Applications that require real-time feedback
  • Decentralized exchanges and trading platforms
  • Onchain games or apps with frequent state updates
  • Interfaces that benefit from faster feedback such as live dashboards

Using Flashblocks with Unichain Endpoints​

Flashblocks is currently supported on the Unichain and can be accessed using your existing Quicknode Unichain endpoint — no additional add-ons are required.

NetworkFlashblocks Availability
Unichain Mainnet✅
Unichain Sepolia✅

Supported RPC Methods​

Access Flashblocks preconfirmations through your Unichain endpoint by using the pending tag on methods like eth_getBlockByNumber, eth_getBalance, and eth_getTransactionCount. Additionally, fetch Flashblocks related transaction details via methods such as eth_getTransactionReceipt and eth_getTransactionByHash. You can also use eth_subscribe over WebSocket to stream real-time Flashblock data including new transactions, pending logs, and block state updates, and stop active streams when needed using eth_unsubscribe.

MethodDescription
eth_callWith "pending", executes contract calls using Flashblock state
eth_getBalanceWith "pending", reflects balances from the latest Flashblock
eth_getBlockByNumberWith "pending", returns the most recent Flashblock
eth_getLogsWith "pending", returns logs from the latest Flashblock
eth_getTransactionByHashReturns the transaction with the specified hash
eth_getTransactionCountWith "pending", returns the updated nonce from Flashblocks
eth_getTransactionReceiptReturns receipts for preconfirmed transactions
eth_subscribeSubscribes to real-time Flashblock events via WebSocket (e.g., newFlashblocks, newFlashblockTransactions, pendingLogs)
eth_unsubscribeUnsubscribes from an active WebSocket subscription created with eth_subscribe

Resources​