Sign/Verify a message

You can sign and verify messages in just 1 line of code.

With Cometh Connect, we deploy a smart account for our users.

When you use a smart account, you need to follow the EIP1271 standard for signature verification. You have to call the isValidSignature function available on the smart contract (here is a more detailed explanation). We created a library that facilitates smart account signature verification using viem.

With Connect, we deploy the smart account at the first transaction of the user, allowing to reduce gas cost for our clients (it's a feature called lazy deployment). You might want to verify the signature of a wallet that is not yet deployed.

To facilitate that, we created an endpoint that allows you to verify an account signature, whether the account is deployed or not:

Verify signature

post

Verify the signature for a given message following EIP1271. This will work even if the safe wallet is not deployed yet as it will use the predicted wallet address for the EOA that signed the message.

Path parameters

walletAddressstringRequired

A wallet address

Example: 0x7Fc751C1725F3B955Aa8781640E1BAf5B75684c2Pattern: ^0x[a-fA-F0-9]{40}$

Header parameters

apikeystringRequired

A string representation of a customer ApiKey.

Example: 4fd84958-1bab-4e1c-9778-46d2639d3196

Body

signaturestringRequired

The signature associated to the message.

Example: 0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3Pattern: ^0x[a-fA-F0-9]{40}$

messagestringRequired

Message signed by the user.

Example: hello world

Responses

200

Successfull operation and verification result

application/json

500

Internal server error

application/json

post

HTTPcURLJavaScriptPython

POST /wallets/:walletAddress/is-valid-signature HTTP/1.1
Host: api.connect.cometh.io
apikey: 4fd84958-1bab-4e1c-9778-46d2639d3196
Content-Type: application/json
Accept: */*
Content-Length: 82

{
  "signature": "0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3",
  "message": "hello world"
}

{
  "success": true,
  "result": true
}

In practice, this is what it looks like:

import {
  ComethWallet,
  ConnectAdaptor,
  ComethProvider,
  SupportedNetworks
} from '@cometh/connect-sdk'

const api = axios.create({ baseURL: "https://api.connect.cometh.io"});
api.defaults.headers.common["apikey"] = API_KEY;

const walletAdaptor = new ConnectAdaptor({
  chainId: YOUR_CHAIN_ID,
  apiKey: API_KEY
})

const wallet = new ComethWallet({
  authAdapter: walletAdaptor,
  apiKey: API_KEY,
  rpcUrl: RPC_URL
})

await wallet.connect(OPTIONAL_WALLET_ADDRESS)

const message = "hello world";
const signature = await wallet.signMessage(message);

const body = { message, signature };
const response = await api.post(`/wallets/${walletAddress}/is-valid-signature`, body);

const verificationResult = response.data.result