Sponsor fees for your users

Cover gas, bridging, and swap fees for your users with a single deposit.

Transaction fees are one of the biggest UX barriers in crypto. With Rhinestone’s fee sponsorship, you deposit USDC once and the SDK covers gas, bridging, and swap fees for your users across any supported chain. No per-chain setup required.

This tutorial builds on the Quickstart. You’ll need a working smart account setup before continuing.

Prerequisites

• Completed the Quickstart
• A Rhinestone dashboard account with an API key
• USDC on Base (testnet USDC from Circle Faucet for testing)

Steps

1. Top up your sponsorship balance

   Open the Rhinestone dashboard and go to the Sponsorship tab.

   Press Deposit, enter an amount of USDC, and confirm the transaction in your wallet. Your balance updates automatically once the transaction is confirmed.

   On testnets, sponsorship works out of the box with no deposit required. For production, reach out to get your deposit address set up.
2. Send a sponsored transaction

   Add sponsored: true when preparing the transaction:

   const prepared = await account.prepareTransaction({
     sourceChains: [arbitrum],
     targetChain: base,
     calls: [
       {
         to: recipientAddress,
         value: 0n,
         data: '0x',
       },
     ],
     sponsored: true,
   })
   const signed = await account.signTransaction(prepared)
   const result = await account.submitTransaction(signed)
   
   const status = await account.waitForExecution(result)
   console.log('Transaction settled:', status)
   

   Your user signs once. The Rhinestone orchestrator deducts the fees from your sponsorship balance and the user pays nothing.

3. Sponsor selectively (optional)

   You can choose which fee types to cover:

   const transaction = await account.prepareTransaction({
     sourceChains: [arbitrum],
     targetChain: base,
     calls: [...],
     sponsored: {
       gas: true,
       bridging: true,
       swaps: false,
     },
   })
   

   Or apply sponsorship conditionally on your backend. For example, only sponsor transactions that interact with your app’s contract:

   function shouldSponsor(calls: { to: string }[]): boolean {
     const appContract = '0xYourContractAddress'
     return calls.some((call) => call.to.toLowerCase() === appContract.toLowerCase())
   }
   
   const calls = [{ to: '0xYourContractAddress', value: 0n, data: encodedCalldata }]
   
   const transaction = await account.prepareTransaction({
     sourceChains: [arbitrum],
     targetChain: base,
     calls,
     sponsored: shouldSponsor(calls),
   })
   

Next steps

Gas & Fee Sponsorship reference

Full details on fee types, policies, and how sponsorship is calculated.

Signer types

Customise your signer: passkeys, embedded wallets, multi-factor auth.

Add session keys

Give users one-click UX with scoped session keys and onchain permissions.