Documentation>Quick Start

Quick Start

Get gasless transactions working in your Aptos dApp in minutes

Which method should I use?
Method 1 — Wallet AdapterMethod 2 — Script Composer
Transaction typesAny — transfers, contracts, NFTsToken transfers only
TestnetAlways freeAlways free
Mainnet costCredits deducted ($0.01 min)Fee from the token (~$0.01)
Code to add3 lines — drop-in replacement~30 lines — build, sign, submit
Best forExisting dApps, any transactionStablecoin transfers, no credits needed

How billing works

Testnet is always free. Method 1 on mainnet deducts credits from your dashboard balance — from $0.01 per transaction. Method 2 has no credits — the fee comes from the token being sent.

Method 1 — Wallet Adapter Integration
Drop-in replacement. Works with any transaction type, any wallet.
App.tsx
TypeScript
1import { SmoothSendTransactionSubmitter } from '@smoothsend/sdk';
2import { AptosWalletAdapterProvider } from '@aptos-labs/wallet-adapter-react';
3import { Network } from '@aptos-labs/ts-sdk';
4 
5function App() {
6  // Step 1 — create the submitter with your API key
7  const smoothSend = new SmoothSendTransactionSubmitter({
8    apiKey: process.env.NEXT_PUBLIC_SMOOTHSEND_API_KEY!,
9    network: 'testnet', // or 'mainnet'
10  });
11 
12  // Step 2 — pass it to the wallet provider (that's it!)
13  return (
14    <AptosWalletAdapterProvider
15      dappConfig={{ network: Network.TESTNET, transactionSubmitter: smoothSend }}
16    >
17      <YourApp />
18    </AptosWalletAdapterProvider>
19  );
20}
21 
22// Step 3 — use wallet functions as normal. Now gasless!
23const { signAndSubmitTransaction } = useWallet();
24const result = await signAndSubmitTransaction({ data: payload });

Works for

  • • Any transaction type — transfers, contracts, NFT mints, DeFi
  • • Testnet: completely free, no setup required
  • • Mainnet: credits deducted from your dashboard ($0.01 minimum per tx)
Advanced — useSmoothSend Hook (Per-Function Routing)
Use this when only some functions should be gasless. Each component decides independently — sponsored functions go through SmoothSend, others use the user's own APT.
providers.tsx + TodoList.tsx
TypeScript
1// providers.tsx — plain wallet provider, no transactionSubmitter
2import { AptosWalletAdapterProvider } from '@aptos-labs/wallet-adapter-react';
3import { Network } from '@aptos-labs/ts-sdk';
4 
5export function Providers({ children }: { children: React.ReactNode }) {
6  return (
7    <AptosWalletAdapterProvider dappConfig={{ network: Network.MAINNET }}>
8      {children}
9    </AptosWalletAdapterProvider>
10  );
11}
12 
13// TodoList.tsx — per-component hook
14import { useSmoothSend } from '@smoothsend/sdk';
15import { SmoothSendTransactionSubmitter } from '@smoothsend/sdk';
16 
17const submitter = new SmoothSendTransactionSubmitter({
18  apiKey: process.env.NEXT_PUBLIC_SMOOTHSEND_API_KEY!,
19  network: 'mainnet',
20});
21 
22function TodoList() {
23  // signAndSubmitTransaction auto-routes:
24  //   sponsored functions  → fee-payer gasless (user pays 0 APT)
25  //   non-sponsored        → user pays gas normally
26  const { signAndSubmitTransaction } = useSmoothSend(submitter);
27 
28  const handleDelete = async (id: number) => {
29    // delete_todo is whitelisted in Sponsorship Rules → gasless
30    const result = await signAndSubmitTransaction(buildDeleteTodoPayload(id));
31    console.log('Tx hash:', result.hash);
32  };
33}

When to choose useSmoothSend over transactionSubmitter

  • • You want specific contract functions sponsored, not all transactions
  • • You have user-pays actions (e.g. "create" costs gas) alongside free actions (e.g. "delete" is free)
  • • You manage sponsorship via the Sponsorship Rules allowlist in your dashboard
Method 2 — Script Composer (Fee-in-Token)
Mainnet token transfers where the fee is deducted from the token. No credits needed.
transfer.ts
TypeScript
1import { ScriptComposerClient } from '@smoothsend/sdk';
2import { Deserializer, SimpleTransaction } from '@aptos-labs/ts-sdk';
3import { useWallet } from '@aptos-labs/wallet-adapter-react';
4 
5const client = new ScriptComposerClient({
6  apiKey: process.env.NEXT_PUBLIC_SMOOTHSEND_API_KEY!,
7  network: 'mainnet',
8});
9 
10async function transferUSDC(walletAddress: string) {
11  const { signTransaction } = useWallet();
12 
13  // Step 1 — build the transaction (fee shown before signing)
14  const build = await client.buildTransfer({
15    sender: walletAddress,
16    recipient: '0xRecipientAddress',
17    amount: '1000000',    // 1 USDC (6 decimals)
18    assetType: '0xbae207659db88bea0cbead6da0ed00aac12edcdda169e591cd41c94180b46f3b',
19    decimals: 6,
20    symbol: 'USDC',
21  });
22  console.log('Fee:', build.feeBreakdown.formatted.fee); // e.g. "0.01 USDC"
23 
24  // Step 2 — deserialize and sign with the connected wallet
25  const txBytes = new Uint8Array(build.transactionBytes);
26  const transaction = SimpleTransaction.deserialize(new Deserializer(txBytes));
27  const signedTx = await signTransaction({ transactionOrPayload: transaction });
28 
29  // Step 3 — submit
30  const result = await client.submitSignedTransaction({
31    transactionBytes: Array.from(txBytes),
32    authenticatorBytes: Array.from(signedTx.authenticator.bcsToBytes()),
33  });
34  console.log('Tx hash:', result.txHash);
35}

Works for

  • • Mainnet stablecoin transfers: USDT, USDC, WBTC, USDe, USD1
  • • No credits needed — tiny fee deducted from the token (~$0.01)
  • • Users sign with their wallet; relayer pays the APT gas
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