> ## Documentation Index
> Fetch the complete documentation index at: https://docs.startale.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Send transactions

> Send a single transaction from the user's smart account.

Send a transaction the same way you would with any wagmi-compatible wallet. The user's smart account is the sender.
For details on who pays gas and how to configure sponsorship, see [Gas sponsorship](/app-sdk/gasless).

## Send native value

```tsx theme={null}
import { useSendTransaction } from 'wagmi'
import { parseEther } from 'viem'

const { sendTransactionAsync } = useSendTransaction()

const hash = await sendTransactionAsync({
  to: '0x000000000000000000000000000000000000dEaD',
  value: parseEther('0.001'),
})
```

## Call a contract

```tsx theme={null}
import { useWriteContract } from 'wagmi'
import { erc20Abi } from 'viem'

const { writeContractAsync } = useWriteContract()

const hash = await writeContractAsync({
  address: USDSC_ADDRESS,
  abi: erc20Abi,
  functionName: 'transfer',
  args: [recipient, amount],
})
```

## With the raw provider

```ts theme={null}
const hash = await provider.request({
  method: 'eth_sendTransaction',
  params: [
    {
      to: '0x000000000000000000000000000000000000dEaD',
      value: '0x38d7ea4c68000', // 0.001 ETH in wei
    },
  ],
})
```

The `from` field is set automatically to the user's smart account. If you supply a `from` value, it is ignored.

## How gas works in Mini Apps

When your Mini App runs inside the Startale App, every `eth_sendTransaction` call is gasless for the user. Here is exactly what happens under the hood:

1. **Context detection.** The App SDK detects it is running inside the Startale App iframe and automatically routes requests through the host wallet instead of opening a standalone popup.

2. **Conversion to a UserOperation.** The SDK converts the `eth_sendTransaction` call into an ERC-4337 UserOperation using the [AA SDK](https://github.com/StartaleGroup/scs-aa-sdk). This is what allows the transaction to carry a paymaster signature.

3. **Paymaster capability injection.** Before the request reaches the wallet, the SDK automatically injects an [EIP-5792](https://eips.ethereum.org/EIPS/eip-5792) `paymasterService` capability into the `wallet_sendCalls` payload:
   ```ts theme={null}
   capabilities: {
     paymasterService: {
       url: "<SCS_PAYMASTER_URL>",
       id: "<HOST_PAYMASTER_ID>",
     }
   }
   ```
   This happens in the SDK's request interceptor — your code does not need to pass any paymaster configuration.

4. **AA SDK builds and signs the UserOperation.** The Startale App's backend uses `createSCSPaymasterClient` from the AA SDK to fetch a paymaster signature for the UserOperation. The paymaster co-signs the UserOp, committing to cover the gas cost.

5. **Bundler submission.** The signed UserOperation is submitted to the SCS Bundler, which packages it and calls `handleOps` on the EntryPoint contract. Gas is paid by the Startale paymaster, not the user.

**As a Mini App developer, you do not configure anything.** There is no `paymasterOptions`, no paymaster URL, and no `paymasterId` in your code. The Startale App host owns the paymaster and injects it transparently.

For standalone dApps outside the Startale App, gas sponsorship requires explicit configuration. See [Gas sponsorship](/app-sdk/gasless) for the full breakdown and the `paymasterOptions` reference.

For batched calls or atomic multi-step transactions, see [Batched calls](/app-sdk/batched-calls).

## Errors

| Code   | Meaning                                    |
| ------ | ------------------------------------------ |
| `4001` | User rejected the transaction in the popup |
| `4100` | Wallet not connected                       |
| `4900` | Provider disconnected                      |

See [Errors](/app-sdk/errors) for the full list.