Sponsor fees for your users

Cover gas, bridging, and swap fees for your users.

Transaction fees are one of the biggest UX barriers in crypto. With Rhinestone’s fee sponsorship, you save a card once and the SDK covers gas, bridging, and swap fees for your users across any supported chain, billed to you monthly. 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
• For mainnet sponsorship, a card saved in the dashboard (see Billing). Testnets need nothing.

Steps

1. Enable sponsorship billing

   Open the Rhinestone dashboard and go to Settings → Sponsorship.

   Press Save card and enter your card details. Sponsored usage is then invoiced to your organization monthly — see Billing.

   On testnets, sponsorship works out of the box: no card required, and testnet usage is never billed.
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 adds the fees to your monthly sponsorship usage 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.