> For the complete documentation index, see [llms.txt](https://cetus-1.gitbook.io/cetus-developer-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cetus-1.gitbook.io/cetus-developer-docs/developer/cetus-aggregator/features-available/sponsored-transactions.md).

# Sponsored Transactions

#### Sponsored transaction: sponsor pays gas

Set `sponsored: true` when building the swap. In this mode the swap does not use `txb.gas` as input or output, because the gas coin belongs to the sponsor.

```typescript
import { Transaction } from "@mysten/sui/transactions"
import { SUI_TYPE_ARG } from "@mysten/sui/utils"

const sender = userSigner.toSuiAddress()
const sponsor = sponsorSigner.toSuiAddress()
const txb = new Transaction()

await client.fastRouterSwap({
  router: routerRes,
  txb,
  slippage: 0.01,
  sponsored: true,
})

// Build command-only bytes. Pass sender so CoinWithBalance can resolve
// the user's input coins before the sponsor adds gas data.
const txKindBytes = await client.buildTransactionKind(txb, sender)

const { objects: gasCoins } = await client.client.listCoins({
  owner: sponsor,
  coinType: SUI_TYPE_ARG,
  limit: 1,
})

const sponsorCoins = gasCoins.map((coin) => ({
  objectId: coin.objectId,
  version: coin.version,
  digest: coin.digest,
}))

const sponsoredTx = client.buildSponsoredTransaction({
  txKindBytes,
  sender,
  sponsor,
  sponsorCoins,
  gasBudget: "100000000",
})

const result = await client.signAndExecuteSponsoredTransaction(
  sponsoredTx,
  userSigner,
  sponsorSigner
)
```

For gas-station integrations, the sponsored transaction flow can be split between the user and the sponsor:

1\. The user builds the command-only transaction bytes by calling `buildTransactionKind`.

2\. The sponsor converts those transaction-kind bytes into a full sponsored transaction by attaching gas data, including `gasOwner` and `gasPayment`.

3\. Both the user and the sponsor sign the same full transaction bytes.

4\. The fully signed transaction is then submitted to the network.