Send Transaction With Viem

Runtime Requirements

• Runtime: Node.js 18+
• Required package:

  viem

• Required network input:

  RPC_URL

Required Secrets / Inputs

• SEED_PHRASE

  or

  PRIVATE_KEY

  (exactly one signer source per send)

• RPC_URL

  ,

  chain

  ,

  to

  ,

  amountEth

• Ask for explicit consent before reading env-based signer secrets

Required Inputs

• signer source:

  seedPhrase

  or

  privateKey

• rpcUrl

• chain

  (for example

  mainnet

  ,

  sepolia

  , or custom chain object)

• to

  address

• amountEth

  (human readable amount)

Workflow

1. Identify signer input:
   • seed phrase path: derive account with

     mnemonicToAccount

   • private key path: derive account with

     privateKeyToAccount

2. Create

   publicClient

   and

   walletClient

   .
3. Validate

   to

   with

   isAddress

   .
4. Convert value with

   parseEther(amountEth)

   .
5. Optionally run a preflight check:
   • read sender balance
   • estimate gas
6. Require explicit send confirmation before broadcast:
   • confirm chain, recipient, amount, and estimated fee
7. If chain is mainnet, require a second explicit confirmation.
8. Send transaction with

   walletClient.sendTransaction

   .
9. Return tx hash, from/to addresses, amount, and chain summary.

Viem Example (Seed Phrase)

import { createPublicClient, createWalletClient, http, parseEther, isAddress } from 'viem'
import { sepolia } from 'viem/chains'
import { mnemonicToAccount } from 'viem/accounts'

const account = mnemonicToAccount(process.env.SEED_PHRASE!)
const publicClient = createPublicClient({ chain: sepolia, transport: http(process.env.RPC_URL!) })
const walletClient = createWalletClient({ account, chain: sepolia, transport: http(process.env.RPC_URL!) })

const to = '0xabc...'
if (!isAddress(to)) throw new Error('Invalid recipient address')

const hash = await walletClient.sendTransaction({
  account,
  to,
  value: parseEther('0.001'),
})

Viem Example (Private Key)

import { createPublicClient, createWalletClient, http, parseEther, isAddress } from 'viem'
import { sepolia } from 'viem/chains'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`)
const publicClient = createPublicClient({ chain: sepolia, transport: http(process.env.RPC_URL!) })
const walletClient = createWalletClient({ account, chain: sepolia, transport: http(process.env.RPC_URL!) })

const to = '0xabc...'
if (!isAddress(to)) throw new Error('Invalid recipient address')

const hash = await walletClient.sendTransaction({
  account,
  to,
  value: parseEther('0.001'),
})

Guardrails

• Use

  parseEther

  for human-to-wei conversion.
• Validate addresses with

  isAddress

  .
• Never expose mnemonic or full private key in output.
• Ask for explicit confirmation before mainnet sends.
• Stop and report if funds are insufficient for value + gas.
• Default to read-only simulation if user has not approved broadcast.

Failure Handling

• Insufficient funds -> report required (amount + fee) vs available balance.
• Nonce too low/replacement error -> re-fetch pending nonce and retry once with user confirmation.
• RPC timeout/network error -> retry with backoff, then ask for alternate RPC if still failing.
• Chain mismatch (expected vs connected) -> stop and request chain confirmation before sending.

Standard Response Contract

• action

  :

  send

• chain

  : chain id/name used

• address

  : sender wallet address

• txHash

  : transaction hash after broadcast, else

  null

• status

  :

  success

  |

  failed

  |

  needs_confirmation

• next_step

  : one clear follow-up action