# Send bundles to BuildAI

Users can send Flashbots bundles to one of the URLs below.

#### Bundle Relay URLs[​](https://docs.flashbots.net/flashbots-auction/advanced/rpc-endpoint#bundle-relay-urls) <a href="#bundle-relay-urls" id="bundle-relay-urls"></a>

| Network | URL                           |
| ------- | ----------------------------- |
| Mainnet | `https://buildai.net`         |
| Sepolia | `https://buildai.net/sepolia` |

JSON-RPC methods supported:

#### eth\_sendBundle[​](https://docs.flashbots.net/flashbots-auction/advanced/rpc-endpoint#eth_sendbundle) <a href="#eth_sendbundle" id="eth_sendbundle"></a>

`eth_sendBundle` can be used to send your bundles to our builder. The `eth_sendBundle` RPC has the following payload format:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_sendBundle",
  "params": [
    {
      txs,               // Array[String], A list of signed transactions to execute in an atomic bundle
      blockNumber,       // String, a hex encoded block number for which this bundle is valid on
      minTimestamp,      // (Optional) Number, the minimum timestamp for which this bundle is valid, in seconds since the unix epoch
      maxTimestamp,      // (Optional) Number, the maximum timestamp for which this bundle is valid, in seconds since the unix epoch
      revertingTxHashes, // (Optional) Array[String], A list of tx hashes that are allowed to revert
      refundPercent,     // (Optional) Number, the percentage (from 0 to 99) of bundle tip that should be passed back to the refundRecipient
      refundRecipient,   // (Optional) Address, account that will receive the refund from this bundle, defaults to the sender of the first transaction
    }
  ]
}
```

If the **refundPercent** field is set, the builder will pass refundPercent of the bundle tip minus the cost of the refund transfer to the **refundRecipient**. If the cost of the refund transfer is greater than the refund amount, the bundle will still be included, but no refund will occur.

example:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_sendBundle",
  "params": [
    {
      "txs": ["0x123abc...", "0x456def..."],
      "blockNumber": "0xb63dcd",
      "minTimestamp": 0,
      "maxTimestamp": 1615920932,
      "refundPercent": 10,
      "refundRecipient": "0x123abc..."
    }
  ]
}
```

example response:

```
{
  "jsonrpc": "2.0",
  "id": "1",
  "result": {
    "bundleHash": "0x2228f5d8954ce31dc1601a8ba264dbd401bf1428388ce88238932815c5d6f23f"
  }
}
```

**Note: Flashbots signature header is not required.**