Paymaster & Gas Sponsorship

Tenzro's ERC-4337 v0.8 account abstraction includes a full Paymaster implementation that allows application developers to sponsor gas fees for their users. Users interact with the network without holding TNZO — the application's master wallet covers all transaction fees. This enables Web2-like onboarding where users never see gas costs.

How It Works

Paymaster Configuration

import { TenzroClient, Paymaster } from "@tenzro/sdk";

const client = new TenzroClient("https://rpc.tenzro.network");

// Deploy a paymaster funded by your master wallet
const paymaster = await client.paymaster.deploy({
  masterWallet: "0xYourMasterWallet...",
  initialDeposit: "100000000000000000000", // 100 TNZO
  maxGasPerUser: "1000000000000000000",    // 1 TNZO max per user op
  allowedOperations: ["transfer", "inference", "identity"],
});

console.log("Paymaster address:", paymaster.address);

// Top up paymaster deposit
await client.paymaster.deposit(paymaster.address, "50000000000000000000");

// Check paymaster balance
const balance = await client.paymaster.getDeposit(paymaster.address);
console.log("Deposit:", balance, "TNZO");

Sponsored Transactions

With a paymaster deployed, user transactions are automatically sponsored. The user signs the operation but pays zero gas:

import { TenzroClient } from "@tenzro/sdk";

const client = new TenzroClient("https://rpc.tenzro.network");

// User sends a sponsored transaction
const tx = await client.sponsored.sendTransaction({
  paymaster: "0xPaymasterAddress...",
  userOp: {
    sender: "0xUserSmartAccount...",
    to: "0xRecipient...",
    value: "0",
    callData: "0x...", // Contract call
  },
});

// The user paid 0 TNZO in gas
// The paymaster paid the actual gas cost from its deposit

// Sponsor an inference request (user pays nothing)
const result = await client.sponsored.inference({
  paymaster: "0xPaymasterAddress...",
  model: "gemma3-270m",
  messages: [{ role: "user", content: "Hello" }],
});

AppClient Pattern

The AppClient is the recommended pattern for building applications on Tenzro. It combines a master wallet (for gas sponsorship) with user management and smart accounts:

import { AppClient } from "@tenzro/sdk";

// Initialize your application client
const app = new AppClient({
  rpcUrl: "https://rpc.tenzro.network",
  masterWallet: process.env.MASTER_WALLET_KEY,
  paymaster: "0xYourPaymaster...",
  appName: "MyAIApp",
});

// Register a new user (auto-provisions identity + smart account)
const user = await app.registerUser({
  externalId: "user-123",   // Your app's user ID
  displayName: "Alice",
});

// user.address  — Smart account address
// user.did      — TDIP DID (did:tenzro:human:...)
// user.wallet   — MPC wallet (2-of-3, auto-provisioned)

// Execute operations on behalf of the user (gas-free)
await app.executeFor(user.address, {
  operation: "inference",
  model: "gemma3-270m",
  messages: [{ role: "user", content: "Summarize this document" }],
});

Master Wallet Funding

# Fund the master wallet from the testnet faucet
curl -X POST https://api.tenzro.network/api/faucet \
  -H "Content-Type: application/json" \
  -d '{"address": "0xMasterWallet..."}'

# Fund a user wallet from the master wallet
curl -X POST https://rpc.tenzro.network \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_sendRawTransaction",
    "params": ["0xsigned_tx_from_master_to_user..."],
    "id": 1
  }'

ERC-4337 Details