author_submitExtrinsic - JSON-RPC Method

Description

Submits a fully formatted and signed extrinsic (transaction) to the Polkadot Asset Hub transaction pool for inclusion in a block. This method is essential for broadcasting transactions to the network.

Parameters

Parameter	Type	Required	Description
extrinsic	string	Yes	Hex-encoded signed extrinsic to submit to the network

Returns

Field	Type	Description
result	string	Transaction hash of the submitted extrinsic

Request Example

{
  "jsonrpc": "2.0",
  "method": "author_submitExtrinsic",
  "params": [
    "SIGNED_EXTRINSIC_HEX"
  ],
  "id": 1
}

The placeholder SIGNED_EXTRINSIC_HEX must be replaced with a fresh, signed extrinsic that includes a valid nonce for your account before submission.

Response Example

{
  "jsonrpc": "2.0",
  "result": "0x0a3620274b55e0bae28b2e55f28ad0af0a49350d1305b6fff211bad2979751b0",
  "id": 1
}

Code Examples

cURL

curl https://api-asset-hub-polkadot.n.dwellir.com/YOUR_API_KEY \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "author_submitExtrinsic",
    "params": ["SIGNED_EXTRINSIC_HEX"],
    "id": 1
  }'

Python

import requests
import json

def submit_extrinsic(signed_extrinsic: str) -> str:
    url = "https://api-asset-hub-polkadot.n.dwellir.com/YOUR_API_KEY"
    headers = {"Content-Type": "application/json"}

    payload = {
        "jsonrpc": "2.0",
        "method": "author_submitExtrinsic",
        "params": [signed_extrinsic],
        "id": 1,
    }

    response = requests.post(url, headers=headers, data=json.dumps(payload), timeout=30)
    data = response.json()

    if "error" in data:
        raise RuntimeError(f"RPC Error: {data['error']}")

    return data["result"]

# Example usage
signed_hex = "SIGNED_EXTRINSIC_HEX"
tx_hash = submit_extrinsic(signed_hex)
print(f"Transaction hash: {tx_hash}")

JavaScript

const submitExtrinsic = async (signedExtrinsic) => {
  const response = await fetch('https://api-asset-hub-polkadot.n.dwellir.com/YOUR_API_KEY', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      jsonrpc: '2.0',
      method: 'author_submitExtrinsic',
      params: [signedExtrinsic],
      id: 1,
    }),
  });

  const data = await response.json();
  return data.result; // Transaction hash
};

// Example usage
const txHash = await submitExtrinsic('SIGNED_EXTRINSIC_HEX');
console.log('Transaction submitted:', txHash);

How to obtain a signed extrinsic

1. Choose a tool — Use Polkadot.js Apps, @polkadot/api, subxt, or an offline signer that supports the Asset Hub runtime.
2. Build and sign your call — In Polkadot.js Apps open Developer → Extrinsics, craft the transaction, sign it with an account that has funds, and copy the Hex-encoded call. With @polkadot/api, call api.tx.<pallet>.<method>(...).signAsync(account) and then .toHex() on the signed extrinsic.
3. Submit promptly — Broadcast the freshly signed payload immediately. If you need to retry, increment the nonce and re-sign; replaying the same hex will fail.
4. (Optional) Verify in a block — After submission, fetch the containing block via chain_getBlock to confirm the extrinsic landed as expected.

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Need help? Contact our support team or check the Asset Hub documentation.