Build a Validity Transaction

This guide uses an EIP-1559 transaction with Viem because it is the recommended transaction type. The API also supports signed legacy and EIP-2930 transactions.

base_sendRawTransactionValidity is available on Base Mainnet and Base Sepolia through the sequencer endpoints listed in Connect to Base, and on Vibenet.

1. Create Predicates

Use balance, nonce, or storage to wait for account or contract state. Use block_number and flashblock_index to constrain the candidate position. Every predicate must match.

Predicate setup

import type { Address, Hex } from 'viem';

const validity = [
  {
    type: 'balance',
    params: {
      address: '0x8ba1f109551bD432803012645Ac136ddd64DBA72' as Address,
      op: '>=',
      value: '0x1' as Hex,
    },
  },
  {
    type: 'storage',
    params: {
      address: '0x8ba1f109551bD432803012645Ac136ddd64DBA72' as Address,
      slot: '0x8' as Hex,
      op: '=',
      value: '0x2a' as Hex,
    },
  },
  {
    type: 'block_number',
    params: { op: '<=', value: '0x11a6a1' as Hex },
  },
  {
    type: 'flashblock_index',
    params: { op: '<=', value: '0x2' as Hex },
  },
] as const;

Omit mask to compare the full storage word. The block_number value 0x11a6a1 is a placeholder. Set it to the latest block number plus 10 right before you sign, so the bound falls within the 60-second expiry window. Use flashblock_index to target a position within a Flashblock. Valid flashblock_index values range from 1 through 10, inclusive; the example uses 0x2 (index 2).

2. Sign an EIP-1559 Transaction

Use the sender’s next nonce. The signed payload becomes the first RPC parameter.

Sign transaction

import { createPublicClient, http, type Chain } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';

const client = createPublicClient({ chain, transport: http(rpcUrl) });
const account = privateKeyToAccount(privateKey);
const fees = await client.estimateFeesPerGas();
const nonce = await client.getTransactionCount({
  address: account.address,
  blockTag: 'latest',
});

const rawTransaction = await account.signTransaction({
  chainId: (chain as Chain).id,
  type: 'eip1559',
  nonce,
  to: '0x...' as Address,
  data: '0x...' as Hex,
  value: 0n,
  gas: 100_000n,
  maxFeePerGas: fees.maxFeePerGas,
  maxPriorityFeePerGas: fees.maxPriorityFeePerGas,
});

3. Submit the Transaction

Pass the signed transaction and validity as separate parameters.

Submit transaction

const response = await fetch(rpcUrl, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'base_sendRawTransactionValidity',
    params: [rawTransaction, { validity }],
  }),
});

const body = await response.json();
if (body.error) throw new Error(body.error.message);
const hash = body.result;

4. Check Inclusion

The RPC returns a transaction hash. Use eth_getTransactionReceipt to check for an onchain receipt. For field definitions, see Validity Transaction RPC.

Specifications

Reference

Node Operators

Security

1. Create Predicates

2. Sign an EIP-1559 Transaction

3. Submit the Transaction

4. Check Inclusion

​1. Create Predicates

​2. Sign an EIP-1559 Transaction

​3. Submit the Transaction

​4. Check Inclusion

1. Create Predicates

2. Sign an EIP-1559 Transaction

3. Submit the Transaction

4. Check Inclusion