@tychilabs/ugf-testnet-js

This is the UGF testnet SDK. It runs the full UGF execution lifecycle against Base Sepolia only, using TYI_MOCK_USD as a mock settlement coin. Users send transactions without holding any destination-chain ETH.

No paymasters. No bundlers. No ERC-4337. No Smart Wallets.

What Is a Remote Transaction

A Remote Transaction routes an onchain action to its destination without making the user move liquidity first.

Normally: user lacks destination-chain ETH → action fails.

With UGF: user authorizes settlement from an existing balance → UGF completes the action at destination.

Value here.  →  UGF routes.  →  Action there.

This testnet environment runs that full lifecycle against Base Sepolia using TYI_MOCK_USD as a mock settlement coin. It is the integration surface for wallets, dApps, and agents building completion flows before connecting to production routes.

Gasless transactions on Base Sepolia — gas paid in TYI mock USD.

Use Cases

Wallets — let users send ERC-20 tokens or interact with contracts on Base Sepolia without holding ETH. User pays in TYI mock USD, wallet handles the rest.

dApps — onboard users who have no gas token. Any contract call (swap, mint, vote, transfer) can be submitted gaslessly during testnet integration.

AI agents — agents execute onchain actions without managing gas wallets per chain. Pay once in TYI, agent's action lands on-chain.

Protocol teams — test full transaction lifecycle (quote → settle → execute → confirm) before connecting to production UGF routes on mainnet.

Network

| Field | Value | | --------------- | -------------- | | Chain | Base Sepolia | | Chain ID | 84532 | | Chain type | evm | | Settlement coin | TYI_MOCK_USD |

Exported constants:

BASE_SEPOLIA_CHAIN_ID; // "84532"
BASE_SEPOLIA_CHAIN_TYPE; // "evm"
TYI_USD_PAYMENT_COIN; // "TYI_MOCK_USD"

Install

npm install @tychilabs/ugf-testnet-js ethers

Quick Start

import { ethers } from "ethers";
import {
  BASE_SEPOLIA_CHAIN_ID,
  BASE_SEPOLIA_CHAIN_TYPE,
  TYI_USD_PAYMENT_COIN,
  UGFClient,
} from "@tychilabs/ugf-testnet-js";

const provider = new ethers.JsonRpcProvider("https://sepolia.base.org");
const wallet = new ethers.Wallet(PRIVATE_KEY, provider);

const client = new UGFClient();

// 1. Authenticate — prove wallet ownership to UGF
await client.auth.login(wallet);

// 2. Quote — describe the destination action, receive settlement amount + digest
const quote = await client.quote.get({
  payer_address: wallet.address,
  tx_object: JSON.stringify({
    from: wallet.address,
    to: "0xRecipient",
    data: "0x",
    value: "0",
  }),
});

// 3. Settle — authorize TYI transfer via ERC-3009 signature (no on-chain tx from user)
await client.payment.x402.execute({ quote, signer: wallet });

// 4. Execute — UGF sponsors ETH at destination, SDK confirms completion
const { userTxHash } = await client.chains.evm.sponsorAndExecute(
  quote.digest,
  wallet,
  async () => ({
    to: "0xRecipient",
    data: "0x",
    value: 0n,
  }),
);

quote.get() defaults to Base Sepolia and TYI_MOCK_USD when fields are omitted. Passing any other chain or coin throws UGFError with code UNSUPPORTED_TESTNET_ROUTE.

sponsorAndExecute receives a TransactionRequest builder — do not set gasLimit, gasPrice, or type. The SDK caps gas to the sponsored budget automatically.

Remote Transaction Lifecycle

1. Authenticate
   auth.login → EIP-191 wallet signature → JWT

2. Quote
   quote.get → POST /quote → digest + TYI settlement_amount

3. Settle
   payment.x402.execute → ERC-3009 typed-data signature → gateway pulls TYI

4. Execute
   chains.evm.sponsorAndExecute
     ├── poll /status until settlement confirmed
     ├── wait for sponsored ETH to land at destination
     ├── estimate gas, cap to sponsored budget
     ├── send legacy tx (type 0)
     └── POST /evm/confirm → userTxHash

5. Confirm
   userTxHash → action completed on Base Sepolia

Each stage maps to a distinct UGF concern:

• Quote — price the destination action
• Settle — authorize value transfer from source
• Execute — complete the action at destination
• Confirm — close the route and return proof

Client Surface

client.auth; // authenticate signer
client.registry; // discover supported routes and settlement tokens
client.quote; // price a destination action
client.payment.x402; // settle via ERC-3009 authorization
client.payment.vault; // settle via on-chain vault payment
client.status; // poll route completion
client.chains.evm; // execute and confirm EVM destination actions

Gateway Endpoints

GET  /auth/nonce?address=<address>
POST /auth/wallet-login
GET  /tokens/registry
POST /quote
POST /payment/submit
GET  /status?digest=<digest>
POST /evm/confirm

Error Reference

| Code | Stage | Meaning | | --------------------------- | ------- | ------------------------------------------------ | | UNSUPPORTED_TESTNET_ROUTE | Quote | Chain or coin not available on testnet | | QUOTE_ERROR | Quote | Route cannot be priced or digest missing | | NO_PROVIDER | Settle | Signer must have an attached provider | | SETTLEMENT_ERROR | Settle | Authorization signature failed or rejected | | VAULT_TX_FAILED | Settle | On-chain vault payment receipt missing or failed | | EXECUTION_ERROR | Execute | Destination action stopped before confirmation | | COMPLETION_TIMEOUT | Confirm | Confirmation not received within timeout window |

Surface errors at the exact lifecycle stage — avoid generic "transaction failed" messages so users know where the route stopped.

Example

npx tsx examples/evm-tyi-gasless-sdk.ts

Compatibility

| Environment | Status | | ----------------------- | ---------- | | Node.js 18+ | Supported | | Browser (ethers signer) | Supported | | React Native | Not tested |

About

This is the testnet SDK — Base Sepolia only, TYI_MOCK_USD only.

The production SDK @tychilabs/ugf-sdk supports mainnet routes across EVM chains, Solana, Sui, and Tron with real settlement coins.

Tychi Labs builds UGF — Remote Transaction infrastructure for wallets, apps, and agents. UGF is a Value-to-Action API: source-chain value authorizes destination-chain action, without destination-chain setup.

• Mainnet SDK: @tychilabs/ugf-sdk
• Execution proof: ugfscan.com
• Docs: universalgasframework.com
• X: @TychiLabs