Multicall

0.15.2 verified Sat May 09 auth: no python

Aggregate results from multiple Ethereum contract calls into a single RPC call, using the MakerDAO Multicall contract. Current version 0.15.2, compatible with Python >=3.10 and <4. Release cadence is irregular.

pip install multicall

Common errors

error EthCallError: No data returned from call at block ↓

cause The target contract or block does not exist, or the RPC endpoint is faulty.

fix

Verify the contract address and RPC URL. Ensure the block is within the chain's range.

error AttributeError: 'Multicall' object has no attribute 'aggregate' ↓

cause Using the old API on multicall >=0.10.0 which removed `.aggregate()`.

fix

Call the instance directly: multi() instead of multi.aggregate().

error ValueError: Address must be checksummed ↓

cause Passing an address without proper EIP-55 checksumming.

fix

Use Web3.to_checksum_address('0x...') on the address.

Warnings

breaking In version 0.10.0, the API changed from using `Multicall.aggregate()` to calling the instance directly `multi()`. Old code using `.aggregate()` will break. ↓

fix Replace `.aggregate()` with a direct call: `multi()` instead of `multi.aggregate()`.

deprecated The `_w3` argument is deprecated in favor of passing a `web3` instance directly to the `Multicall` constructor. ↓

fix Use `Multicall(..., web3=w3)` instead of `Multicall(..., _w3=w3)`.

gotcha Call targets must be checksummed addresses; passing an address without correct checksum will raise an error. ↓

fix Use `Web3.to_checksum_address()` on all addresses before passing to `Call`.

Imports

Multicall

wrong

from multicall import Multicall

correct

from multicall import Multicall

No common wrong import; always use this.

Call
wrong
```
from multicall import Multicall
```
correct
```
from multicall import Call
```
Call is a separate class; do not import from Multicall.

Quickstart

Create a Multicall instance with a list of Call objects, then call it to aggregate results.

from multicall import Multicall, Call
from web3 import Web3

w3 = Web3(Web3.HTTPProvider('https://mainnet.infura.io/v3/YOUR-PROJECT-ID'))
multi = Multicall([
    Call(('0x...', 'balanceOf(address)(uint256)'), [['0x...', None]]),
], _w3=w3)
result = multi()
print(result)