​
Overview

Web3 transactions typically involve interacting with smart contracts on the blockchain, with applications extending to decentralized applications (dApps), non-fungible tokens (NFTs), and beyond. This guide will outline how developers can create Web3 transactions in MPC Wallets using the APIs provided by Cobo.

Note: The code samples below are only applicable to Web3 Wallets under the MPC Wallets.

​
Code Samples

​
Initiating a withdraw transaction using Web3 Wallets (e.g., sending 0.01 ETH)

Step 1: Initialize the mpc_client

Step 2: Create the withdraw transaction

from cobo_custody.client.mpc_client import MPCClient
from cobo_custody.config import DEVELOP_ENV
from cobo_custody.signer.local_signer import LocalSigner
import time

api_secret = "your api secret"  # your wallet api secret
chain_code = "ETH"  # your target chain
coin_code = "ETH"  # your target coin
amount = "100000000000000000"  # withdraw amount：0.01ETH
from_address = "your mpc wallet address"  # your mpc wallet address
to_address = "to address"  # to address

# init cobo client
mpc_client = MPCClient(signer=LocalSigner(api_secret), env=DEVELOP_ENV, debug=False)

request_id = f"MPCTransaction-{int(time.time() * 1000)}" # your custom request_id
# create withdraw transaction
response = mpc_client.create_transaction(
   coin=coin_code,
   request_id=request_id,
   amount=amount,
   from_addr=from_address,
   to_addr=to_address,
   gas_price=6500000000,
   gas_limit=21000,
)
print(f"Withdraw: {response.result}")

​
Interacting with a smart contract using Web3 Wallets

Step 1: Initialize the mpc_client

Step 2: Pass in calldata to call a smart contract

from cobo_custody.client.mpc_client import MPCClient
from cobo_custody.config import DEVELOP_ENV
from cobo_custody.signer.local_signer import LocalSigner
import time

api_secret = "your api secret"  # your wallet api secret
chain_code = "ETH"  # your target chain
coin_code = "ETH"  # your target coin
amount = "0"
from_address = "your mpc wallet address"  # your mpc wallet address
to_address = "contract address"  # contract address
extra_parameters = '{"calldata": "0xa8059cbb000000000000000000000000971948873f869e4517311b190d7eb31e30eba0ef000000000000000000000000000000000000000000000000002386f26fc10000"}' # use calldata to call or deploy contract

# init cobo client
mpc_client = MPCClient(signer=LocalSigner(api_secret), env=DEVELOP_ENV, debug=False)

request_id = f"MPCTransaction-{int(time.time() * 1000)}" # your custom request_id

response = mpc_client.create_transaction(
   coin=coin_code,
   request_id=request_id,
   amount=amount,
   from_addr=from_address,
   to_addr=to_address,
   gas_price=6500000000,
   gas_limit=22385,
   extra_parameters=extra_parameters,
)
print(f"call contract: {response.result}")

For more information on the ‘create_transaction’ endpoint, please click here.

Setting Up Token SweepingEstimating Transaction Fees