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.

post

/wallets/:walletAddress/is-valid-signature

Path parameters

walletAddressstringrequired

A wallet address

Example: 0x7Fc751C1725F3B955Aa8781640E1BAf5B75684c2

Pattern: ^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: 0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3

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

messagestringrequired

Message signed by the user.

Example: hello world

Responses

application/json

application/json

cURL

JavaScript

Python

HTTP

cURL

curl -L \
  --request POST \
  --url 'https://api.connect.cometh.io/wallets/:walletAddress/is-valid-signature' \
  --header 'apikey: 4fd84958-1bab-4e1c-9778-46d2639d3196' \
  --header 'Content-Type: application/json' \
  --data '{"signature":"0x4D33B9C8A02EC9a892C98aA9561A3e743dF1FEA3","message":"hello world"}'

200

500

200

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

Successfull operation and verification result

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