Quickstart

This guide walks an onboarded partner through their first notification.

Prerequisites

A dedicated Cashback endpoint URL (provided by nexroute during onboarding)
Source IPs allowlisted on that endpoint (coordinated during onboarding; see Authentication)

Method

The endpoint speaks JSON-RPC 2.0 over HTTPS and WebSocket. One method is exposed:

eth_notifyRawTransaction: notify nexroute of a single user-signed transaction that you are dispatching yourself. nexroute uses it to construct and race a backrun; it never dispatches your transaction.

Any other method returns -32601 method not found.

Notify, then dispatch

The point of Async mode is that notification never delays dispatch. Send the notification and your own dispatch concurrently; don’t await the acknowledgment first.

curl -X POST <YOUR_CASHBACK_ENDPOINT> \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_notifyRawTransaction",
    "params": [{ "tx": "<RAW_SIGNED_TX>" }]
  }'

// fire the notification without awaiting it...
const notification = fetch('<YOUR_CASHBACK_ENDPOINT>', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'eth_notifyRawTransaction',
    params: [{ tx: '<RAW_SIGNED_TX>' }],
  }),
});

// ...and dispatch through your own path immediately
await dispatchThroughYourPath(rawSignedTx);

// inspect the acknowledgment later, e.g. for logging
const data = await (await notification).json();
console.log(data.result); // 0x... tx hash

Params is a single-element array containing an object with tx, the hex-encoded raw signed transaction (0x-prefixed). The object shape mirrors eth_sendPrivateRawTransaction and reserves room for optional fields without further wire breaks.

Response

The endpoint returns a JSON-RPC envelope echoing the request id. The result field contains the transaction hash (0x-prefixed, 32 bytes).

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x6b6f1c8f5d2c4a9d3e1f8b7c6a5d4e3f2c1b0a9d8e7f6a5b4c3d2e1f0a9b8c7d"
}

A non-error response confirms the notification was accepted for backrun analysis. It says nothing about delivery: dispatch, inclusion, and mempool privacy of the transaction remain yours.

Errors

Errors follow standard JSON-RPC conventions:

Code	Cause
`-32601`	Method other than `eth_notifyRawTransaction`
`-32000`	Malformed transaction (RLP decode failure, invalid signature)
`-32603`	Internal error (rare; the notification is dropped and your transaction is unaffected)

Treat errors as diagnostics, not failures to handle inline: your dispatch must never depend on the notification succeeding.

Next steps

Authentication: IP allowlist setup and operational notes
Security: what nexroute guarantees about notified transactions
eth_notifyRawTransaction: full method specification

Getting started

Dispatch mode

Async mode

Embedded mode

API reference

Prerequisites

Method

Notify, then dispatch

Response

Errors

Next steps

​Prerequisites

​Method

​Notify, then dispatch

​Response

​Errors

​Next steps

Prerequisites

Method

Notify, then dispatch

Response

Errors

Next steps