author_submitAndWatchExtrinsic - JSON-RPC Method

Description

Sends a signed extrinsic to the Enjin Matrix transaction pool and establishes a subscription that streams status updates (e.g., Ready, InBlock, Finalized). This method is useful for client-side UX, backend job orchestration, or exchange integrations that must confirm inclusion and finality.

Parameters

Parameter	Type	Required	Description
extrinsic	string	Yes	Signed, SCALE-encoded extrinsic

Returns

The subscription ID is returned immediately. Subsequent notifications carry status updates.

Request Example

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "author_submitAndWatchExtrinsic",
  "params": [
    "0x29028400..."
  ]
}

Sample Notifications

{
  "jsonrpc": "2.0",
  "method": "author_extrinsicUpdate",
  "params": {
    "subscription": "0x0000000000000001",
    "result": { "status": "Ready" }
  }
}

{
  "jsonrpc": "2.0",
  "method": "author_extrinsicUpdate",
  "params": {
    "subscription": "0x0000000000000001",
    "result": {
      "status": {
        "InBlock": "0x1873093eade39aa409f64537dd972c27156e4691fc0fda227a06d50c52ad5fef"
      }
    }
  }
}

{
  "jsonrpc": "2.0",
  "method": "author_extrinsicUpdate",
  "params": {
    "subscription": "0x0000000000000001",
    "result": {
      "status": {
        "Finalized": "0x1873093eade39aa409f64537dd972c27156e4691fc0fda227a06d50c52ad5fef"
      }
    }
  }
}

To stop receiving updates, call author_unwatchExtrinsic with the subscription ID.

Code Examples

JavaScript (Polkadot.js)

import { ApiPromise, WsProvider } from '@polkadot/api';
import { Keyring } from '@polkadot/keyring';

const provider = new WsProvider('wss://api-enjin-matrixchain.n.dwellir.com/YOUR_API_KEY');
const api = await ApiPromise.create({ provider });
const keyring = new Keyring({ type: 'sr25519' });
const signer = keyring.addFromUri('//Alice');

const unsub = await api.tx.balances
  .transfer('efS1ZdvCHHviX7qnTGZEZQX9Uz3qpibG9L5RpF9niM8ne5RBn', 10 ** 18)
  .signAndSend(signer, ({ status }) => {
    if (status.isInBlock) {
      console.log('Included at', status.asInBlock.toHex());
    } else if (status.isFinalized) {
      console.log('Finalized at', status.asFinalized.toHex());
      unsub();
    }
  });

WebSocket Flow

ws.send(JSON.stringify({
  jsonrpc: '2.0',
  id: 1,
  method: 'author_submitAndWatchExtrinsic',
  params: ['0xSIGNED_EXTRINSIC']
}));

// ...process notifications...

ws.send(JSON.stringify({
  jsonrpc: '2.0',
  id: 2,
  method: 'author_unwatchExtrinsic',
  params: ['0x0000000000000001']
}));

Best Practices

• Always unsubscribe after finality to prevent resource leaks.
• Combine with payment_queryInfo and feeMultiplier monitoring to surface fee information alongside status updates.
• Retry submissions with exponential backoff when the subscription returns an error payload.