How to verify an IMPT carbon retirement

Step-by-step walkthrough for independently verifying an IMPT booking's on-chain carbon retirement.

Direct answer

Use any Ethereum JSON-RPC client to filter the CarbonCreditNFT Retired event log by bookingRef. The retirement record proves both the burn and the on-chain inventory deduction.

What you need

Your IMPT booking confirmation (carries the bookingRef).
An Ethereum JSON-RPC endpoint (Alchemy, Infura, public node, your own).
A library — ethers.js, viem, web3.py, or just curl + the JSON-RPC API.

Step 1 — get the contract address

CarbonCreditNFT v2 is at 0xF473eA545dF03a57beF96BAf96188a6b6d673050. Verified on Etherscan; ABI available there.

Step 2 — query the Retired event log

Filter logs by topic[0] = keccak("Retired(uint256,uint256,address,bytes32)") and topic[3] = your bookingRef (32-byte). The matching log is your retirement evidence.

Step 3 — parse the result

The log carries: tokenId (which credit batch retired), amount (1 tonne, denominated as 1 in token units for v2), holder (beneficiary address), bookingRef (your booking).

Step 4 — cross-check with registry

Optional: query Thallo's API or the source registry directly for the registry-side retirement record. Match by retirement reference.

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