Bundles are one of the most important tools for transacting onchain. They allow users to privately express conditions and requirements that go beyond what is possible in normal transaction submission. Bundles are primarily used by specialized actors known as searchers for activities like onchain arbitrage or applications looking for precise inclusion or revert protection.
Bundles on L1 Ethereum are expressed using the eth_sendBundle method and allow users to submit transactions privately to block builders. Bundles on Unichain work similarly, with transactions being privately submitted to Unichain using the eth_sendBundle method. Bundles then remain active for up to 10 blocks or until their max block number or timestamp is reached. Expired bundles will return an error code, signaling the transaction was dropped from the mempool. The first iteration of bundles on Unichain will be limited to single transactions to enforce priority fee ordering.
Here are some examples for how you can use bundles on Unichain:
Arbitrage Operations
// Execute arbitrage only if profitable within next 3 blocksconst arbitrageBundle = { txs: [signedArbitrageTx], minBlockNumber:0x${(currentBlock + 1).toString(16)}, maxBlockNumber:0x${(currentBlock + 3).toString(16)}// Revert protection prevents paying gas if opportunity disappears};Time-Sensitive DeFi Operations
// Execute a trade only during a specific time windowconst timedTradeBundle = { txs: [signedTradeTx], minTimestamp: auctionStartTime, maxTimestamp: auctionEndTime};MEV Protection
// Protect against MEV by constraining execution timingconst protectedBundle = { txs: [signedTx], minBlockNumber:0x${targetBlock.toString(16)}, maxBlockNumber:0x${targetBlock.toString(16)}// Execute in specific block only};
We are excited to see advanced transaction submission with bundles, block ranges and revert protection go live on Unichain and Rollup-Boost! Explore the eth_sendBundle on Unichain documentation here and learn more about Unichain at Unichain.org.
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