Transaction Decoder

WHAT IT DOES

Transaction Decoder takes any transaction hash and converts raw calldata into a human-readable function call. Paste a transaction hash and instantly see the sender, recipient, value, gas limit, and most importantly—the decoded function name and its parameters with values. If you provide the contract's ABI, the tool decodes the full function call, showing you exactly what the transaction does: which function was called, what arguments were passed, and their values. Without an ABI, it still shows the function selector and raw data, giving you a starting point for investigation. This is essential for developers debugging smart contracts, auditors reviewing transactions, or anyone who wants to understand what a transaction really does.

HOW TO USE

Connect your EVM wallet (optional—the tool works read-only). Select the network from the dropdown. Enter a transaction hash (0x…66) and optionally paste the contract ABI JSON array in the text area. Click "decode" to fetch the transaction from the chain. The tool displays the transaction metadata and, if an ABI is provided, decodes the calldata into the function name and a list of parameters with their values. If no ABI is provided, it shows the function selector and raw data. Use the "clear" button to reset and start a new decode. No signing or approvals required.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 via the BGWallet provider. It fetches the transaction using provider.getTransaction(txHash). If an ABI is provided, it creates an ethers.utils.Interface and uses interface.parseTransaction() to decode the calldata, extracting the function name and arguments. The decoded parameters are filtered to remove duplicate indexed entries and displayed as key-value pairs. If no ABI is provided, the tool shows the raw calldata and extracts the first 4 bytes as the function selector (using calldata.slice(0, 10)). The tool also displays basic transaction metadata: from, to, value, and gas limit. All values are formatted for readability, with BigNumber values converted to strings.

WHAT IT CANNOT SEE

This tool cannot decode transactions without a matching ABI or known function signature—if the ABI is missing or incomplete, you will only see the raw selector and data. It cannot decode private or unverified contract implementations where the ABI is not publicly available. It cannot decode transactions that use proxy patterns beyond the provided ABI—if you provide the proxy ABI instead of the implementation, decoding will fail. It cannot decode cross-chain or off-chain transaction data. It cannot show the transaction receipt or event logs. Historical data is limited by the RPC provider's availability; older transactions may be unavailable.

PLEASE NOTE

Works exclusively on EVM-compatible chains: Ethereum Mainnet, Goerli, Sepolia, Polygon, Arbitrum, and Optimism. Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. This is a read-only, free developer tool—use it for debugging and transaction analysis, but always cross-check critical data with a block explorer or your own node. The tool requires a valid transaction hash that exists on the selected network.