# TxEnvelopeTempo.getFeePayerSignPayload

Returns the fee payer payload to sign for a [`TxEnvelopeTempo.TxEnvelopeTempo`](/tempo/reference/TxEnvelopeTempo/types#txenvelopetempo).

Fee sponsorship uses a dual-signature scheme: the sender signs the transaction, then a fee payer signs over the transaction with the sender's address to commit to paying fees. The fee payer's signature includes the `feeToken` and `sender_address`, using magic byte `0x78` for domain separation.

[Fee Payer Signature](https://docs.tempo.xyz/protocol/transactions/spec-tempo-transaction#fee-payer-signature) [Fee Sponsorship Guide](https://docs.tempo.xyz/protocol/transactions#fee-sponsorship)

## Imports

:::code-group
```ts [Named]
import { TxEnvelopeTempo } from 'ox/tempo'
```

```ts [Entrypoint]
import * as TxEnvelopeTempo from 'ox/tempo/TxEnvelopeTempo'
```
:::

## Examples

```ts twoslash
// @noErrors
import { Secp256k1 } from 'ox'
import { TxEnvelopeTempo } from 'ox/tempo'

const envelope = TxEnvelopeTempo.from({
  chainId: 1,
  calls: [
    {
      data: '0xdeadbeef',
      to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8'
    }
  ],
  nonce: 0n,
  maxFeePerGas: 1000000000n,
  gas: 21000n
})

const payload = TxEnvelopeTempo.getFeePayerSignPayload(
  envelope,
  {
    sender: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045'
  }
) // [!code focus]
// @log: '0x...'

const signature = Secp256k1.sign({
  payload,
  privateKey: '0x...'
})
```

## Definition

```ts
function getFeePayerSignPayload(
  envelope: TxEnvelopeTempo,
  options: getFeePayerSignPayload.Options,
): getFeePayerSignPayload.ReturnValue
```

**Source:** [src/tempo/TxEnvelopeTempo.ts](https://github.com/wevm/ox/blob/main/src/tempo/TxEnvelopeTempo.ts#L1168)

## Parameters

### envelope

* **Type:** `TxEnvelopeTempo`

The transaction envelope to get the fee payer sign payload for.

#### envelope.accessList

* **Type:** `readonly { address: abitype_Address; storageKeys: readonly 0x${string}[]; }[]`
* **Optional**

EIP-2930 Access List.

#### envelope.authorizationList

* **Type:** `readonly { address: abitype_Address; chainId: numberType; nonce: bigintType; signature: SignatureEnvelope; }[]`
* **Optional**

EIP-7702 (Tempo) Authorization list for the transaction.

#### envelope.calls

* **Type:** `readonly Call[]`

Array of calls to execute.

#### envelope.chainId

* **Type:** `numberType`

EIP-155 Chain ID.

#### envelope.feePayerSignature

* **Type:** `{ r: 0x${string}; s: 0x${string}; yParity: numberType; }`
* **Optional**

Fee payer signature.

#### envelope.feeToken

* **Type:** `Address.Address | undefined`
* **Optional**

Fee token preference. Address of the TIP-20 token.

#### envelope.from

* **Type:** `Address.Address | undefined`
* **Optional**

Sender of the transaction.

#### envelope.gas

* **Type:** `bigintType`
* **Optional**

Gas provided for transaction execution

#### envelope.keyAuthorization

* **Type:** `Signed`
* **Optional**

Key authorization for provisioning a new access key.

When present, this transaction will add the specified key to the AccountKeychain precompile,
before verifying the transaction signature.
The authorization must be signed with the root key, the tx can be signed by the Keychain signature.

#### envelope.maxFeePerGas

* **Type:** `bigintType`
* **Optional**

Total fee per gas in wei (gasPrice/baseFeePerGas + maxPriorityFeePerGas).

#### envelope.maxPriorityFeePerGas

* **Type:** `bigintType`
* **Optional**

Max priority fee per gas (in wei).

#### envelope.nonce

* **Type:** `bigintType`
* **Optional**

Unique number identifying this transaction

#### envelope.nonceKey

* **Type:** `bigintType`
* **Optional**

Nonce key for 2D nonce system (192 bits).

#### envelope.signature

* **Type:** `SignatureEnvelope`
* **Optional**

#### envelope.type

* **Type:** `type`

Transaction type

#### envelope.validAfter

* **Type:** `numberType`
* **Optional**

Transaction can only be included in a block after this timestamp.

#### envelope.validBefore

* **Type:** `numberType`
* **Optional**

Transaction can only be included in a block before this timestamp.

### options

* **Type:** `getFeePayerSignPayload.Options`

Options.

#### options.sender

* **Type:** `abitype_Address`

Sender address to cover the fee of.

## Return Type

The fee payer sign payload.

`getFeePayerSignPayload.ReturnValue`