> ## Documentation Index
> Fetch the complete documentation index at: https://docs.theblockchainlibrary.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ABI Encode/Decode (Python)

> Encode and decode ABI-calldata in Python for contract interaction.

# ABI Encode/Decode (Python)

Encode and decode ABI-calldata in Python for contract interaction.

Encode and decode ABI-calldata in Python for contract interaction.

## Explanation

ABI encoding is how Ethereum serializes function arguments. The selector is the first 4 bytes of keccak(signature). eth\_abi.encode packs the arguments. This is useful when building raw calldata or decoding logs without a full contract instance.

## Code

```python theme={null}
from eth_abi import encode, decode
from eth_utils import keccak, to_hex

# Encode function call: transfer(address,uint256)
signature = "transfer(address,uint256)"
selector = keccak(signature.encode())[:4]

encoded_args = encode(
    ["address", "uint256"],
    ["0x1234...address", 1_000_000_000_000_000_000]
)

calldata = selector + encoded_args
print("Calldata:", to_hex(calldata))

# Decode the response
response = encode(["bool"], [True])
decoded = decode(["bool"], response)
print("Decoded:", decoded)  # (True,)
```

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**Canonical knowledge ID:** `code-example:abi-encode-decode-python`