FAQ

General

What is Carbonized?

A carbon-credit marketplace on EVM chains. Credits are created by authorized issuers as ERC-721 NFTs (CarbonCreditNFT), wrapped into fungible ERC-20 CCT (CarbonCreditToken), and traded for payment token on CarbonMarketplace through an order book and auctions. See Architecture.

Is it live on mainnet?

Not by default. The public deployment is on Robinhood Chain Testnet (chain ID 46630), where nothing has monetary value. Robinhood Chain mainnet (chain ID 4663, real 6-decimal payment token) is being prepared: see Robinhood Chain Mainnet. The contracts are unaudited, and the app shows a "Testnet / unaudited" banner on every build that is not configured for robinhood-mainnet.

What is real and what is mocked?

Mainnet has no mock contracts. Details per page: Web App.

Which languages does the app support?

English and Chinese (中文). Use the language toggle in the app's top bar; the choice is remembered in your browser.

Which market is Carbonized aimed at?

Carbonized is aimed at the Chinese market. Its ICM_COMPLIANCE pool is meant for national-registry compliance credits (for example CCER credits), alongside voluntary standards such as Verra VCS and Gold Standard. The testnet carries no real credits.

Wallet and network

How do I connect?

With the Connect Wallet button, which uses Reown AppKit (WalletConnect, needs NEXT_PUBLIC_REOWN_PROJECT_ID). Injected wallets such as MetaMask also work. See Reown AppKit.

Where do I get gas and payment token?

Gas on testnet: the Robinhood testnet faucet in Networks. Test payment token exists only on testnet: call the open mint on the mock payment token; steps in Buy credits. On mainnet you need real ETH for gas and real payment token from an exchange or bridge; there is no faucet.

Is there a free starter pack of credits?

No. The app and the contracts have no starter pack, faucet or free-credit path. Credits exist only when an authorized issuer has issued them, and you obtain them by buying on the marketplace or from an issuer.

How do I become an issuer?

An admin has to grant ISSUER_ROLE to your address, ideally a multisig. Follow the issuer onboarding policy; the current issuers are listed publicly on the Issuer page. Holding the role does not imply any registry or regulatory approval.

Tokens

What is the difference between the NFT and CCT?

Each NFT is one unique credit with metadata (project, methodology, vintage, tonnes, oracle proof hash, serial). CCT is fungible: wrapping an NFT locks it in the CCT contract and mints CCT equal to its tonnes (1 tonne = 1e18 units). Only CCT trades on the marketplace; only NFTs can be retired onchain.

Is a credit "verified"?

The contracts only guarantee that a credit was created by an account holding ISSUER_ROLE, with a non-empty registry serial and a non-zero oracle proof hash, and that the same serial cannot be tokenized twice. The NFT does not call the oracle contracts, and the oracle contracts are mocked on testnet. Think of a credit as "issued by an authorized issuer"; whether the underlying project is real depends on that issuer.

Why can't I wrap my credit?

The NFT must be yours, unwrapped, not retired, have non-zero tonnes, carry a serial and an oracle proof hash, and its methodology must equal the CCT pool's (Methodology mismatch otherwise). The marketplace is deployed against the VERRA_VCS pool. The Tokenize page shows the exact reason for each credit that cannot be wrapped before you send a transaction.

How many decimals does payment token have?

Real payment token on mainnet has 6 decimals. The app reads decimals() of NEXT_PUBLIC_payment token_ADDRESS once and never assumes 18, and the marketplace reads it in its constructor (2 to 18 accepted). CCT always has 18 decimals (1e18 = 1 tonne). On the marketplace a price is payment-token base units per tonne, so $15 per tonne is 15000000 with 6-decimal payment token. The mock payment token on testnet follows whatever decimals it was deployed with.

Trading

What fees apply?

tradingFeePercent is 25 basis points (0.25 %) by default, adjustable by the admin up to 1 %. In order fills and auction settlements it is deducted from the payment token the seller receives, using the rate at the time the order or auction was created. In AMM swaps it is deducted from the input amount.

What if a payment cannot be delivered?

If the payment token refuses a refund or proceeds transfer (for example because an address is blacklisted), the marketplace credits it to pendingWithdrawals instead of failing the whole trade. The app shows a Claim banner when pendingWithdrawals(you) > 0; clicking it calls claim().

Do I need KYC?

Only for orders created with requiresKYC = true (the maker must still be verified when someone fills it), or if the admin switches on the optional global KYC gate for auctions and the AMM. Verification is set by a KYC_ROLE holder via setKYCStatus. The web app never sets the order flag, so web-created orders have no KYC requirement.

Can orders expire?

The contract supports expiry (expiresIn), but the web app always passes 0, meaning no expiry. Auction end times must be 1 hour to 30 days ahead.

Is there a swap UI?

The marketplace contract has an AMM (addLiquidity, removeLiquidity, swap, quoteAddLiquidity), but the AMM functions are not wired into the web app.

Why don't I see an old order or auction?

The app scans events from NEXT_PUBLIC_DEPLOY_BLOCK when set, otherwise only the last 20,000 blocks. See Troubleshooting.

Retirement and compliance

How do I retire a credit?

Onchain: retireCredit / batchRetire burn the NFT and store a certificate (Carbon Wallet, NFT Credits tab). The optional depository tab (only with a backend configured) has a separate off-chain retire that burns nothing. See Retire credits.

What does a retirement certificate prove?

The app builds a printable certificate from the chain at /app/certificates/<txHash>. It shows green only when the NFT contract's stored record was read and matches the event and the credit is issuer-backed (non-REG project, non-empty serial). A read error shows an amber "Could not verify" state, and unbacked registration/demo credits show an amber notice. In every case it proves that a token was burned, not that the underlying project is real. The retirement reason is a self-declared, unverified statement. See Certificates.

Does registering a company verify it?

No. Registration records your company profile and reported emissions onchain in CarbonRegistry and does not mint any credits. The KYB badge is set later by an account holding VERIFIER_ROLE, for exactly the profile that was reviewed; any later change to name, legal ID, contact details or emissions resets it. See Company.

What personal data goes onchain?

Company or trader name, legal ID (companies), country (traders), emission figures and retirement reasons are public and permanent. Email and phone are not onchain: only a salted contactHash is stored, and the details and salt stay in your browser's local storage.

Infrastructure

Do I need the backend?

No. Marketplace, auctions, credit requests, company and trader registration, portfolio and certificates all run onchain. NEXT_PUBLIC_BACKEND_URL is optional, off by default and should stay empty unless you run your own depository backend (when set, company registration sends the registration details, including email and phone, to it). See Troubleshooting.

Why does the dashboard price show an estimate?

The dashboard calls CarbonPriceOracle.getLatestPrice("VERRA_VCS"). The oracle runs Chainlink Functions JavaScript set onchain by the admin (setSource) over price sources, and a fallback reporter holding ORACLE_REPORTER_ROLE can submit a price with reportPrice; the dashboard labels the value Oracle or Manual report from lastPriceManual. On testnet the router is a mock, so there is no fresh Functions price and the dashboard may show its $18.50 fallback labelled as an estimate. Portfolio values are indicative only.

CARB token

Is there a Carbonized token?

A utility token called CARB is planned but is not launched yet. It would only add optional utilities and carries no financial promises. See Token.

Do I need CARB to use Carbonized?

No. Trading, retirement and certificates work without it. CARB would only add optional fee tiers (a discount on the trading fee, never on the price), an issuer bond for the bond-based issuer path, and governance.

Is CARB an investment?

No. There are no returns, yield, staking rewards, revenue share or price commitments. Nothing here is investment advice or an offer or solicitation; rules vary by jurisdiction and CARB may be restricted where you live. The contracts are unaudited; get your own advice.