Decode raw calldata into human-readable transaction intent
Use the calldata decoder to inspect EVM transactions, identify method selectors, read encoded parameters, and understand what a wallet or app is about to execute before or after it lands onchain.
Paste calldata
Drop in a transaction input, router payload, or signed request and turn opaque hex into a readable breakdown.
Identify methods
Extract the 4-byte selector and map it to likely function signatures so contract interactions are easier to audit.
Debug transactions
Review swaps, mints, approvals, and contract calls before building analytics, support workflows, or attribution logic.
How to use the calldata decoder
Use this calldata decoder when you need to turn raw EVM transaction input into a readable contract call. Paste calldata hex from a block explorer, wallet simulation, RPC response, or transaction trace, then review the function selector, ABI-encoded parameters, addresses, token amounts, and nested call data before shipping analytics, debugging a failed transaction, or auditing user intent.
1. Paste EVM calldata
Copy the transaction input from Etherscan, Basescan, a wallet simulation, an RPC call, or a failed transaction trace. The calldata decoder accepts raw hexadecimal input, including the 0x prefix, so you can inspect the exact payload sent to the smart contract.
2. Decode the 4-byte function selector
The first 4 bytes of calldata identify the contract method. Matching that selector to a known function signature helps answer questions like which function was called, whether the transaction is an approval, swap, mint, claim, deposit, bridge, or arbitrary execute call, and what ABI is needed for full decoding.
3. Read ABI-encoded arguments
After the selector, calldata stores typed ABI parameters such as addresses, uint256 values, booleans, bytes, arrays, token IDs, recipient wallets, spenders, amounts, deadlines, and router paths. Decoding those arguments makes raw transaction input easier to review, document, and debug.
4. Map decoded calldata to product analytics
Decoded calldata turns opaque onchain activity into human-readable user intent. Product and data teams can map contract calls to events like approve, swap, mint, stake, claim, subscribe, or bridge, then use those events in funnels, attribution, retention analysis, support workflows, and protocol reporting.