Use web3.js

Cosmostation’s Ethereum provider is EIP-1193 compatible, so you can plug it directly into web3.js and use familiar APIs like requestAccounts, transaction sends, and message signing.

If you’re already using web3 in your dApp, this is one of the quickest ways to get started—just obtain the provider from @cosmostation/extension-client and pass it to new Web3(provider).

import Web3 from 'web3';
import { ethereum, InstallError } from '@cosmostation/extension-client';
try {
  const provider = await ethereum();
  const web3 = new Web3(provider);
  // requestAccounts
  const accounts = web3.eth.requestAccounts();
  // If you want more info, please check out web3.js docs (https://web3js.readthedocs.io)
} catch (e) {
  if (e instanceof InstallError) {
    console.log('not installed');
  }
  // exception
}

Notes

ethereum() returns an EIP-1193 provider, which web3.js can consume as its underlying provider.
web3.eth.requestAccounts() will trigger the wallet UI to ask the user for account access (if not already connected).

signTypedData

eth_signTypedData_v4 is commonly used for EIP-712 typed data signing. It’s typically used for:

off-chain authentication (“Sign in with Ethereum” style flows)
order signing (DEX / marketplace listings)
typed approvals and structured intent signatures

The flow is straightforward:

Build a typed-data payload (msgParams)
Pick the signer address (from)
Call provider.request({ method: 'eth_signTypedData_v4', params: [...] })

const provider = await ethereum();
 
const web3 = new Web3(provider);
 
const msgParams = JSON.stringify({
  domain: {
    // Defining the chain aka Rinkeby testnet or Ethereum Main Net
    chainId: 1,
    // Give a user friendly name to the specific contract you are signing for.
    name: 'Ether Mail',
    // If name isn't enough add verifying contract to make sure you are establishing contracts with the proper entity
    verifyingContract: '0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC',
    // Just let's you know the latest version. Definitely make sure the field name is correct.
    version: '1',
  },
 
  // Defining the message signing data content.
  message: {
    /*
         - Anything you want. Just a JSON Blob that encodes the data you want to send
         - No required fields
         - This is DApp Specific
         - Be as explicit as possible when building out the message schema.
        */
    contents: 'Hello, Bob!',
    attachedMoneyInEth: 4.2,
    from: {
      name: 'Cow',
      wallets: [
        '0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826',
        '0xDeaDbeefdEAdbeefdEadbEEFdeadbeEFdEaDbeeF',
      ],
    },
    to: [
      {
        name: 'Bob',
        wallets: [
          '0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB',
          '0xB0BdaBea57B0BDABeA57b0bdABEA57b0BDabEa57',
          '0xB0B0b0b0b0b0B000000000000000000000000000',
        ],
      },
    ],
  },
  // Refers to the keys of the *types* object below.
  primaryType: 'Mail',
  types: {
    // TODO: Clarify if EIP712Domain refers to the domain the contract is hosted on
    EIP712Domain: [
      { name: 'name', type: 'string' },
      { name: 'version', type: 'string' },
      { name: 'chainId', type: 'uint256' },
      { name: 'verifyingContract', type: 'address' },
    ],
    // Not an EIP712Domain definition
    Group: [
      { name: 'name', type: 'string' },
      { name: 'members', type: 'Person[]' },
    ],
    // Refer to PrimaryType
    Mail: [
      { name: 'from', type: 'Person' },
      { name: 'to', type: 'Person[]' },
      { name: 'contents', type: 'string' },
    ],
    // Not an EIP712Domain definition
    Person: [
      { name: 'name', type: 'string' },
      { name: 'wallets', type: 'address[]' },
    ],
  },
});
 
const from = ''; // signer address
const params = [from, msgParams];
const method = 'eth_signTypedData_v4';
const result = web3.currentProvider.request({
  method,
  params,
});

If you want more detail on how typed data is structured and signed, refer to the official web3.js documentation: https://web3js.readthedocs.io (opens in a new tab)

Provider Use ethers