Contract ABI Decoder

Decode Ethereum smart contract calls from ABI JSON and raw transaction input data.

About Contract ABI Decoder

Smart contract interactions are encoded in hexadecimal transaction data. This tool decodes that data by matching the function selector (first 4 bytes) against your contract's ABI, then extracting and parsing each parameter according to its ABI type. Perfect for developers debugging contract calls, auditors reviewing transactions, or anyone who wants to understand what a smart contract interaction actually does.

Function Call Decoding

Matches the 4-byte function selector against your ABI to identify which function was called, then decodes all parameters with correct types.

Type Support

Handles uint256, address, bytes32, bool, string, arrays, and tuples. Converts hex values to human-readable numbers and addresses.

Common Signature Detection

When no ABI is provided, attempts to recognize common function signatures like transfer, approve, swap, and mint from the selector alone.

Browser-Only Privacy

All decoding happens in your browser with zero external dependencies. Your contract data never leaves your machine.

📋 Common Use Cases

Trade & Investment Analysis

Make data-driven crypto decisions with accurate profit/loss, ROI, and break-even calculations.

Portfolio Management

Track holdings, monitor performance, and maintain target allocations across your crypto investments.

Tax & Record Keeping

Generate accurate records for tax reporting and audit preparation.

DeFi & Strategy Planning

Evaluate staking, yield farming, and investment strategies before committing funds.

🪜 How to Use This Tool

  1. Enter your parameters
    Input amounts, prices, quantities, or addresses depending on the specific crypto tool.
  2. Configure settings
    Set your preferred display currency, tax jurisdiction, or network parameters.
  3. Review analysis
    See calculated results — profit/loss, fees, rewards, or decoded data — with clear breakdowns.
  4. Apply insights
    Use results to inform trading, staking, or development decisions. All data stays in your browser.

📚 Related Guides

Frequently Asked Questions

Are these crypto tools really free?▼
Yes. Every crypto tool on iluv.tools is completely free. No signup, no account, no payment. Everything runs in your browser.
Do I need to connect my wallet?▼
No. None of our crypto tools require wallet connection, transaction signing, or any blockchain interaction. All calculations and validations happen locally in your browser.
Is my crypto data safe?▼
Yes. All data stays in your browser. Portfolio tracker data is stored in localStorage — it never leaves your device. We never see your addresses, balances, or transaction data.