Create Meta Transactions | Tx Relay | Utiliti Developer Docs

Create a new gas-less transaction that is EIP-2771 compatible.

Meta-transactions (gas-less transactions)

Tx Relay is a general-purpose relayer, in the sense that you can use it to send any transaction you want to your contracts. In particular, it can also be used for relaying meta-transactions on behalf of your users. You just need to decide whether or not to relay a given meta-transaction, and then invoke TX Relay for sending it.

This way, you can offer a full gasless experience in your dapp. The same applies to other sidechains supported by Utiliti.

Send EIP-2771 compatible meta-transactions

Tx Relay has a modified API call which additionally takes in a "forwarder_address". This must be a valid Identity Wallet which has been enabled for handling meta-transactions. The transaction will be sent through the forwarder wallet and the "from_address" will be appended to the end of the data.


const response = await fetch('https://api.utiliti.ai/transactions/meta', {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-API-key": "<YOUR_API_KEY_HERE>"
    },
    body: JSON.stringify({
      "chain_id": 5, // Ethereum Goerli
      "from_address": "0xC96524bbeB102d9246ED6a4A07909c7f1Dd2AF8e", // overrides _msgSender() in EIP2771 compatible contracts
      "to_address": "0x23C96144969A9d7c802a96CbF0d539210d176B38", // Contract Address
      "params": { // Contract Parameters
        "from": "0x57a3cdee5886f8f0508f6c0e77c8ec4e74b0238a",
        "to": "0xb1437af7c9735529adb3d33288f6fea4f494e910",
        "tokenId": 2
      },
      "contract_function_name": "safeTransferFrom",
      "abi": "<YOUR_CONTRACT_ABI>",
      "gas_limit": 200000,
      "gas_strategy": "FAST"
      "forwarder_address": "0x0EE553435DE5F9761fdB7b92daa13A28Eb7b7419" // Relay Address
    })
})



SDK coming soon...


CURL *hnd = curl_easy_init();

curl_easy_setopt(hnd, CURLOPT_CUSTOMREQUEST, "POST");
curl_easy_setopt(hnd, CURLOPT_URL, "https://api.utiliti.ai/transactions/meta");

struct curl_slist *headers = NULL;
headers = curl_slist_append(headers, "accept: application/json");
headers = curl_slist_append(headers, "content-type: application/json");
headers = curl_slist_append(headers, "X-API-key: <YOUR_API_KEY_HERE>");
curl_easy_setopt(hnd, CURLOPT_HTTPHEADER, headers);

curl_easy_setopt(hnd, CURLOPT_POSTFIELDS, "{\"chain_id\":5,\"from_address\":\"0xC96524bbeB102d9246ED6a4A07909c7f1Dd2AF8e\",\"to_address\":\"0x23C96144969A9d7c802a96CbF0d539210d176B38\",\"params\":{\"from\":\"0x57a3cdee5886f8f0508f6c0e77c8ec4e74b0238a\",\"to\":\"0xb1437af7c9735529adb3d33288f6fea4f494e910\",\"tokenId\":2},\"contract_function_name\":\"safeTransferFrom\",\"abi\":\"<YOUR_CONTRACT_ABI>\",\"gas_limit\":200000,\"gas_strategy\":\"FAST\",\"forwarder_address\":\"0x0EE553435DE5F9761fdB7b92daa13A28Eb7b7419\"}");

CURLcode ret = curl_easy_perform(hnd);


curl --request POST \
     --url https://api.utiliti.ai/transactions/meta \
     --header 'X-API-key: <YOUR_API_KEY_HERE>' \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --data '
{
     "chain_id": 5,
     "from_address": "0xC96524bbeB102d9246ED6a4A07909c7f1Dd2AF8e",
     "to_address": "0x23C96144969A9d7c802a96CbF0d539210d176B38",
     "params": {
          "from": "0x57a3cdee5886f8f0508f6c0e77c8ec4e74b0238a",
          "to": "0xb1437af7c9735529adb3d33288f6fea4f494e910",
          "tokenId": 2
     },
     "contract_function_name": "safeTransferFrom",
     "abi": "<YOUR_CONTRACT_ABI>",
     "gas_limit": 200000,
     "gas_strategy": "FAST",
     "forwarder_address": "0x0EE553435DE5F9761fdB7b92daa13A28Eb7b7419"
}
'


import requests

url = "https://api.utiliti.ai/transactions/meta"

payload = {
    "chain_id": 5,
    "from_address": "0xC96524bbeB102d9246ED6a4A07909c7f1Dd2AF8e",
    "to_address": "0x23C96144969A9d7c802a96CbF0d539210d176B38",
    "params": {
        "from": "0x57a3cdee5886f8f0508f6c0e77c8ec4e74b0238a",
        "to": "0xb1437af7c9735529adb3d33288f6fea4f494e910",
        "tokenId": 2
    },
    "contract_function_name": "safeTransferFrom",
    "abi": "<YOUR_CONTRACT_ABI>",
    "gas_limit": 200000,
    "gas_strategy": "FAST",
    "forwarder_address": "0x0EE553435DE5F9761fdB7b92daa13A28Eb7b7419"
}
headers = {
    "accept": "application/json",
    "content-type": "application/json",
    "X-API-key": "<YOUR_API_KEY_HERE>"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)