[Ethereum] Get balance of a specific token in python using web3.py on polygon network

polygonweb3.py

I am trying to get the balance in my wallet of specific tokens with no luck.
I have found examples online on how to do this task using web3.js, but the methods used seem to be different. I also found this helpful example: How to view custom token balance in ether wallet using web3, however it doesn't seem to be working for me.

Is anyone able to provide a short script that can do this?

As an example, on the polygon network I expect the wallet address 0xBeD5658e57F54301a23a899674b6593bBf039ab5 to contain 0.882 USDT. Is there anyway to get this programmatically?

Best Answer

You need the token's ABI and utilize the function balanceOf. Example snippet below:

token = w3.eth.contract(address={token address}, abi={token abi}) # declaring the token contract
token_balance = token.functions.balanceOf({your address}).call() # returns int with balance, without decimals

You can find the token ABI from the block explorer, from the code tab of your token. In your case, here you can find the ABI for USDT's contract. You will need to parse JSON before being able to use it in Python.

Edit: I just realized the USDT contract in Polygon doesn't have balanceOf in its ABI. I think you should be able to utilize the ETH ABI no problem.

Related Solutions

[Ethereum] Listen to events in the Polygon network using Web3.py

For future readers, apparently Polygon does not support eth_newFilter so a way to get events thru Web3 is subscribing to logs (currently available thru Web3.js) or using get_logs (if u wanna do it in python), I found an example in a reddit post, goes like this:

from web3 import Web3
from web3._utils.events import get_event_data

w3 = Web3(Web3.HTTPProvider("<Infura host>"))
contract = w3.eth.contract(address="0x33..", abi=abi['abi'])
event_template = contract.events.<EVENT_NAME>
events = w3.eth.get_logs({'fromBlock':from_block, 'toBlock': from_block+10000, 'address':"0x33.."})


def handle_event(event, event_template):
    try:
        result = get_event_data(event_template.web3.codec, event_template._get_event_abi(), event)
        return True, result
    except:
        return False, None

for event in events: 
    suc, res = self.handle_event(event=event, event_template=event_template)   
    if suc:
        print("Event found", res)

Use an Oracle to get a token value on Polygon? (Using web3.js)

Uniswap oracles can be very useful, but they can also be quite risky. Bad actors can manipulate the price in the uniswap pool if the liquidity is low enough, then exploit your protocol using the manipulated price. The tellor oracle, alternatively, includes a token-incentivized dispute mechanism to prevent oracle manipulation for profit. Tellor relies on a network of anon reporters to submit good data, monitor it for faults, and dispute bad data if necessary.

You mentioned that you want to read the ETH/USD feed on chain. Reporters on tellor are currently maintaining that feed actively, so you could simply read the tellor oracle on chain using a getter function, without the need to maintain the feed in any way yourself.