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bundle cancellations

Bundle cancellations are currently deployed to our mainnet staging environment: https://relay-staging.flashbots.net. You must send both bundles and cancellations to this endpoint for it to be successful.

This staging environment is limited to sending and cancelling bundles, and will only simulate bundles targeting currently built and the next blocks. The bundles make it to our staging builder (0x81babe) and you should see the bundles landing on mainnet as you would be using the production endpoint.

Understanding bundle cancellations#

Bundles can be replaced and canceled using a unique identifier (replacementUuid) assigned to a bundle at the time of submission.

{  "jsonrpc": "2.0",  "id": 1,  "method": "eth_sendBundle",  "params": [    {      txs,      blockNumber,      minTimestamp,      maxTimestamp,      revertingTxHashes,      replacementUuid, // UUIDv4 to uniquely identify submission    }  ]}

Replacing bundles#

To replace a bundle, send the new bundle via eth_sendBundle with the same replacementUuid as the bundle you want to replace.

Canceling bundles#

Canceling a bundle will prevent Flashbots builders from including it on-chain. To cancel a bundle, call the eth_cancelBundle endpoint, or use the cancelBundle function in your preferred Flashbots library.

{  "jsonrpc": "2.0",  "id": 1,  "method": "eth_cancelBundle",  "params": [    {      replacementUuid, // UUIDv4 to uniquely identify submission    }  ]}