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Bundles and Orders

Bundles coordinate cross-chain actions

We extend Flashbots bundles with a single field: hostFills. This connects Signet transactions with Ethereum actions:

1{
2  "txs": ["0xabc...", "0xdef..."],
3  "blockNumber": "0x123",
4  "hostFills": {
5    "outputs": [...],
6    "permit": {
7    }
8  }
9}

This straightforward extension enables atomic cross-chain execution: the Signet transactions and the necessary host chain actions either all succeed together or the entire bundle fails.

Bundle Structure

A Signet bundle includes:

  • An array of transactions (txs)
  • Block targeting information (blockNumber, minTimestamp, maxTimestamp)
  • Optional revertingTxHashes identifying Signet transactions allowed to revert without failing the whole bundle
  • Optional replacementUuid for identifying updated bundles
  • The hostFills field containing required host chain actions (if any)

Bundles come in two forms:

  • With host fills:
    • Contain signed orders requiring separate validation
    • The bundle builder tracks and validates these orders
    • Host fills ingest with bundles and pass to submission
  • Without host fills:
    • Standard bundles with typical transactions
    • Processed like regular transaction lists

Bundle Standards

When building systems that handle real value, reliability isn’t optional. That’s why we’ve adopted flashbots-style bundle standards:

  1. Ordering: Transactions execute exactly as specified
  2. Atomicity: All operations succeed or none happen
  3. Revertibility: Transactions only revert when explicitly marked as revertible