chaincodec (Python)

Universal blockchain ABI decoder — production-grade EVM event log and function call decoding, with 50+ built-in DeFi/NFT/bridge protocol schemas.

Install

pip install chaincodec

Prebuilt wheels for Linux (x64, arm64, musl), macOS (x64, arm64), and Windows (x64). No Rust toolchain required.

Quick Start

import asyncio
from chaincodec import EvmDecoder, MemoryRegistry

async def main():
    # Load a schema
    registry = MemoryRegistry()
    registry.load_file("schemas/erc20.csdl")

    decoder = EvmDecoder()

    # Decode an ERC-20 Transfer event
    raw_log = {
        "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "topics": [
            "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
            "0x000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045",
            "0x000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9b",
        ],
        "data": "0x000000000000000000000000000000000000000000000000000000003b9aca00",
    }

    fingerprint = "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
    schema = registry.get_by_fingerprint(fingerprint)

    event = decoder.decode_event(raw_log, schema)
    print(event)
    # DecodedEvent(schema="ERC20Transfer", fields={"from": "0xd8dA...", "to": "0xAb58...", "value": 1000000000})

asyncio.run(main())

Decode Function Calls

from chaincodec import EvmCallDecoder, MemoryRegistry

registry = MemoryRegistry()
registry.load_file("schemas/uniswap-v3.csdl")

decoder = EvmCallDecoder()
call_data = bytes.fromhex("414bf389...")  # exactInputSingle calldata

result = decoder.decode_call(call_data, registry)
print(result.function_name)  # "exactInputSingle"
print(result.inputs)         # [("tokenIn", "0x..."), ("amountIn", 1000000)]

Encode Function Calls

from chaincodec import EvmEncoder, MemoryRegistry

registry = MemoryRegistry()
registry.load_file("schemas/erc20.csdl")

encoder = EvmEncoder()
calldata = encoder.encode_call("transfer", ["0xRecipient...", 1_000_000], registry)
# b'\xa9\x05\x9c\xbb...'

Batch Decode

from chaincodec import EvmDecoder, MemoryRegistry

registry = MemoryRegistry()
registry.load_directory("schemas/")   # loads all 50+ schemas

decoder = EvmDecoder()
events = decoder.decode_batch(raw_logs, registry)
# Parallel decode via Rayon — >1M events/sec

Built-in Schemas (53 protocols)

Links

• GitHub: https://github.com/DarshanKumar89/chainkit
• Rust crates: https://crates.io/crates/chaincodec-core
• npm (Node.js): https://www.npmjs.com/package/@chainfoundry/chaincodec