npm install @biconomy/mexa

import {Biconomy} from "@biconomy/mexa";
import { Web3 } from "web3";
​
// We're creating a 2nd Ethers provider linked to your L2 network of choice
let biconomy = new Biconomy(new Web3.providers.HttpProvider("YOUR RPC URL HERE"),
                                    {apiKey: <API Key>, debug: true});
let networkWeb3 = new Web3(biconomy);
​
/*
    This provider linked to your wallet.
    If needed, substitute your wallet solution in place of window.ethereum 
*/
let walletWeb3 = new Web3(window.ethereum);

biconomy.onEvent(biconomy.READY, () => {
  // Initialize stuff that needs to interact with your node endpoint
  // ie. view calls to contracts
}).onEvent(biconomy.ERROR, (error, message) => {
  // Handle error while initializing mexa
});

let walletSigner = walletProvider.getSigner();
let networkSigner = networkProvider.getSigner();
​
// Initialize Contracts
let contract = new ethers.Contract(<CONTRACT_ADDRESS>,
              <CONTRACT_ABI>, networkSigner.connectUnchecked());
​
let contractInterface = new ethers.utils.Interface(<CONTRACT_ABI>);
​
let address = <wallet public address>; //user address 
​
let functionSignature = contractInterface.encodeFunctionData("addRating", [1,5]);
let gasPrice = await ethersProvider.getGasPrice();
let gasLimit = await ethersProvider.estimateGas({
          to: <CONTRACT_ADDRESS>,
          from: address,
          data: functionSignature
        });
console.log(gasLimit.toString())
​
let rawTx = {
      to: <CONTRACT_ADDRESS>,
      data: functionSignature,
      from: address
    };
    
const metaTxData = await biconomy.getForwardRequestAndMessageToSign(rawTx);
    
console.log(dataToSign);
const hashToSign = metaTxData.personalSignatureFormat;
const signature = await walletSigner.signMessage(hashToSign);
​
let data = {
      signature: signature,
      rawTransaction: signedTx,
      signatureType: biconomy.PERSONAL_SIGN,
    };
​
// send signed transaction with ethers
// promise resolves to transaction hash
let tx = networkProvider.send("eth_sendRawTransaction", [data]);
console.log("Transaction hash : ", tx);     
   
//event emitter for ethers
networkProvider.once(tx, (transaction) => {
      // Emitted when the transaction has been mined
      console.log(transaction);
      //doStuff
    });