How to connect Paymaster and send USDT without fees in 5 minutes

Hello, developers! 👨‍💻

If you are building on Plasma, then the dream of any developer is to allow users to pay with zero. Not in dreams. In fact.

Here’s how it works: Plasma SDK Paymaster is your new best friend. It automatically adds sponsorship data to transactions so that the user pays $0 for USDT transfers, while you top up the pool in $XPL.

Three Steps to Zero-Fee USDT:

Step 1: Install SDK bash npm install @plasma/sdk-paymaster

Step 2: Initialize the client typescript import { PaymasterClient } from '@plasma/sdk-paymaster';

const client = new PaymasterClient({ rpcUrl: 'https://rpc.plasma.to', paymasterAddress: '0xPaymasterUSDT' });

Step 3: Send USDT from sponsorship typescript const tx = await client.sponsorUSDTTransfer({ from: userAddress, to: '0xFriend…', amount: parseUnits('100', 6), // 100 USDT signer: userSigner });

await bundler.sendUserOperation(tx);

What's going on behind the scenes?

✅ Rate limits: up to 100 tx/min per wallet ( configured in the contract )

✅ Security: Whitelist + application registration (registerApp) = no spam

✅ Audit: Quantstamp reviewed SDK 15.08.2025 — report public

✅ Testnet: There is a faucet on testnet.plasma.to for $XPL

Finances for Developers:

The replenishment of the Paymaster pool simply costs: typescript await client.depositToPaymaster({ amount: parseEther('10'), // 10 $XPL signer: devSigner });

Then your users can send USDT without fees until the pool is depleted.

Code ready out of the box: see github.com/plasmafoundation/sdk-paymaster/examples

Tomorrow: How Plasma sponsors developers — grants, hackathons, tools 🚀

Today: Grab SDK, launch on the testnet, share feedback. Questions in the comments!