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

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.

POSThttps://api.connect.cometh.io/wallets/:walletAddress/is-valid-signature

Path parameters

walletAddress*WalletAddress (string)

A wallet address

Example: "0x7Fc751C1725F3B955Aa8781640E1BAf5B75684c2"

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

Header parameters

Body

application/json

signature*string

The signature associated to the message.

Example: "0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3"

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

message*string

Message signed by the user.

Example: "hello world"

Response

200500

Successfull operation and verification result

Body

application/json

success*boolean

Indicates whether the request was successful or not.

Example: true

result*boolean

Indicates if signature is valid.

Example: true

Request

JavaScriptCurlPython

const response = await fetch('https://api.connect.cometh.io/wallets/:walletAddress/is-valid-signature', {
    method: 'POST',
    headers: {
      "apikey": "4fd84958-1bab-4e1c-9778-46d2639d3196",
      "Content-Type": "application/json"
    },
    body: JSON.stringify({
      "signature": "0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3",
      "message": "hello world"
    }),
});
const data = await response.json();

Response

200500

{
  "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