GTE TypeScript SDK (MegaETH Testnet)

A lightweight React-friendly TypeScript SDK that mirrors the gte-python-sdk surface needed for AMM swaps on MegaETH testnet. It wraps the public REST API plus minimal on-chain helpers so a dApp can fetch markets, price tokens, and build approval/swap transactions that follow Uniswap/PancakeSwap v2 conventions.

Features

• ✅ Network config helper (getChainConfig) derived from the Python SDK/testnet docs.
• ✅ Typed REST client for /markets, /tokens, and /markets/{id}/{book|trades|candles} (pairs, TVL, prices, orderbooks, trades, candles).
• ✅ Portfolio endpoint (/users/{address}/portfolio) to render wallet balances in USD.
• ✅ On-chain quoting via the MegaETH Uniswap v2 router (getQuote, getQuoteExactOut).
• ✅ Transaction builders for ERC-20 approvals and swap flows (buildApprove, buildSwapExactIn, buildSwapExactOut).
• ✅ Works in React (fetch + viem under the hood) with examples in examples/.

Installation

npm install gte-typescript-sdk
# or when working locally
npm install
npm run build

Quick start

import { GteSdk } from "gte-typescript-sdk";

const sdk = new GteSdk();
const config = sdk.getChainConfig();
const [market] = await sdk.getMarkets({ marketType: "amm", limit: 1 });

const quote = await sdk.getQuote({
  tokenIn: market.baseToken,
  tokenOut: market.quoteToken,
  amountIn: "0.25", // human-readable units
});

const approveTx = await sdk.buildApprove({
  tokenAddress: market.baseToken.address,
});

const { tx: swapTx } = await sdk.buildSwapExactIn({
  tokenIn: market.baseToken,
  tokenOut: market.quoteToken,
  amountIn: "0.25",
  quote,
  recipient: "0xYourWallet",
});

const quoteOut = await sdk.getQuoteExactOut({
  tokenIn: market.baseToken,
  tokenOut: market.quoteToken,
  amountOut: "1",
});

const { tx: swapExactOutTx } = await sdk.buildSwapExactOut({
  tokenIn: market.baseToken,
  tokenOut: market.quoteToken,
  amountOut: "1",
  quote: quoteOut,
  recipient: "0xYourWallet",
  useNativeIn: true, // optional: native ETH in/out supported when path touches WETH
});

const portfolio = await sdk.getUserPortfolio("0xYourWallet");
console.log(portfolio.totalUsdBalance);

Each builder returns the to, data, and value payload ready to hand to wagmi/ethers/viem for signing.

Heads up on CORS: The public MegaETH endpoints do not send permissive CORS headers, so direct browser calls to https://api-testnet.gte.xyz will fail (TypeError: Failed to fetch). Consume this SDK from a Next.js API route/server component, a custom proxy, or any Node backend. Forward the data/transactions to your React UI rather than instantiating GteSdk in the browser.

Native ETH swaps

If you want to send or receive native ETH, pass useNativeIn and/or useNativeOut to buildSwapExactIn and ensure your quote path starts/ends with the wrapped native token (config.wethAddress).

Examples

• examples/basic.ts – Node script mirroring examples/uniswap_swap.py from the Python SDK.
• examples/react/App.tsx – React component showing how to fetch markets, render a quote, and preview the approval/swap payloads inside DeOperator-style flows.

Run the Node example after building:

npm run build
node --loader ts-node/esm examples/basic.ts

API surface

| Method | Description | | --- | --- | | getChainConfig() | Returns the MegaETH testnet config + router/WETH addresses. | | getMarkets(params) | Calls /markets using the official OpenAPI spec. | | getTokens(params) / getToken(address) | Fetch token metadata from /tokens and /tokens/{address}. | | getMarket(address) | Fetch a single market. | | getMarketTrades(address, params) | Returns /markets/{market}/trades. | | getMarketOrderBook(address, limit?) | Returns /markets/{market}/book. | | getMarketCandles(address, params) | Returns /markets/{market}/candles. | | getUserPortfolio(address) | Returns balances + USD valuations for a wallet from /users/{address}/portfolio. | | getQuote({ tokenIn, tokenOut, amountIn, slippageBps }) | Reads getAmountsOut from the Uniswap v2 router to provide amount + price. | | getQuoteExactOut({ tokenIn, tokenOut, amountOut, slippageBps }) | Reads getAmountsIn for exact-out pricing. | | buildApprove({ tokenAddress, spender?, amount? }) | Encodes an ERC-20 approval; defaults to max approval for the MegaETH AMM router. | | buildSwapExactIn({ tokenIn, tokenOut, amountIn, recipient, quote?, deadlineSeconds?, useNativeIn?, useNativeOut? }) | Builds the swapExact* transaction matching the Python reference implementation. | | buildSwapExactOut({ tokenIn, tokenOut, amountOut, recipient, quote?, deadlineSeconds?, useNativeIn?, useNativeOut? }) | Builds the exact-output counterparts (swap*ForExact*). |

See src/sdk.ts for more detail; all behavior was ported directly from clients/execution in the Python repo.

Development

npm install
npm run build

The SDK is dependency-light (only viem), fully typed, and ready to publish or consume in a React bundler without extra shims.