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This page covers how to deploy, configure, and integrate with the CommodityCustody contract. It assumes you have deployed the Commodity Token suite and have a functioning identity registry and at least one CommodityTokenUpgradeable instance.

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Prerequisites

Before deploying CommodityCustody, the following must be in place:
  1. IdentityRegistryUpgradeable deployed and configured with KYC providers.
  2. At least one CommodityTokenUpgradeable deployed via CommodityTokenFactoryUpgradeable.
  3. USDC (or chosen settlement stablecoin) available on the target chain.
  4. A LiquidationRouter deployed, or a placeholder address if liquidation is not yet needed.

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Compiler Configuration

The batchSettleTrades function takes 9 calldata array parameters plus batchId, which exceeds the EVM’s 16-slot stack limit in the legacy compilation pipeline. The Solidity compiler must use viaIR: true. 
// hardhat.config.js
module.exports = {
  solidity: {
    version: "0.8.24",
    settings: {
      optimizer: { enabled: true, runs: 200 },
      viaIR: true
    }
  }
};
Without this setting, compilation will fail with a stack-too-deep error.

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Deployment Sequence

1
Deploy CommodityCustody
2
Deploy the implementation contract, then deploy an ERC1967Proxy pointing to it and call initialize.
3
const { ethers, upgrades } = require("hardhat");

const CommodityCustody = await ethers.getContractFactory("CommodityCustody");

const custody = await upgrades.deployProxy(
  CommodityCustody,
  [
    "0xADMIN_ADDRESS",            // admin (multi-sig recommended)
    "0xOPERATOR_ADDRESS",         // settlement operator (or 0x0 to default to admin)
    "0xLIQUIDATION_ROUTER",       // router contract address
    "0xUSDC_ADDRESS"              // USDC token address
  ],
  { kind: "uups" }
);

await custody.deployed();
4
ParameterTypeConstraints_adminaddressCannot be zero_operatoraddressZero defaults to admin_liquidationRouteraddressCannot be zero_usdcaddressCannot be zero
5
Register Supported Tokens
6
Register each token the orderbook will trade. Both commodity tokens and USDC are registered the same way.
7
// Register commodity token
await custody.addSupportedToken("0xCOMMODITY_TOKEN");

// Register USDC
await custody.addSupportedToken("0xUSDC_ADDRESS");
8
Configure Commodity Token Compliance
9
The custody contract must be authorized on each commodity token for deposits and withdrawals to succeed. The required configuration depends on the token’s transfer restriction mode:
10
const commodityToken = await ethers.getContractAt(
  "CommodityTokenUpgradeable", "0xCOMMODITY_TOKEN"
);

// WHITELIST mode: whitelist the custody contract
await commodityToken.setWhitelist(custody.address, true);

// BLACKLIST mode: ensure custody is not blacklisted (no action needed if clean)

// KYC required: verify the custody contract address in the identity registry
await identityRegistry.verifyIdentity(
  custody.address,
  keccak256("CUSTODY_CONTRACT"),
  investorType,
  softExpiry,
  hardExpiry
);
11
This step is the most common cause of failed deployments. If the commodity token’s restriction mode changes after deployment, the custody contract must be re-authorized under the new mode.

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Deposit and Withdrawal

Users must deposit tokens into custody before they can place orders on the orderbook. 
// Approve and deposit commodity tokens
await commodityToken.approve(custody.address, ethers.utils.parseEther("100"));
await custody.deposit(commodityToken.address, ethers.utils.parseEther("100"));

// Approve and deposit USDC
await usdc.approve(custody.address, ethers.utils.parseUnits("10000", 6));
await custody.deposit(usdc.address, ethers.utils.parseUnits("10000", 6));
There is no checkTransferability function on CommodityCustody. To pre-check whether a deposit or withdrawal will succeed, query the commodity token’s compliance state directly: 
// Check whitelist status
const isWhitelisted = await commodityToken.whitelist(userAddress);

// Check if account is frozen on the token
const isFrozen = await commodityToken.frozenAccounts(userAddress);

// Check if token is paused
const isPaused = await commodityToken.paused();

// Check KYC status (if kycRequired is true on the token)
const isVerified = await identityRegistry.isVerified(userAddress);
Withdrawals work similarly. The user can only withdraw their available (unlocked) balance, and the commodity token enforces compliance during the on-chain transfer: 
const available = await custody.getAvailableBalance(userAddress, commodityToken.address);
await custody.withdraw(commodityToken.address, available);

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Trade Settlement Flow

The matching engine (operator) follows a lock-then-settle pattern. This is identical to the Stock Orderbook flow.
1
Lock Balances
2
When orders match off-chain, the operator locks both counterparties’ balances.
3
const lockId = ethers.utils.id("lock-001");

// Lock maker's USDC (maker is buyer)
await custody.lockBalance(maker, usdc.address, quoteAmount, lockId);

// Lock taker's commodity tokens (taker is seller)
await custody.lockBalance(taker, commodityToken.address, baseAmount, lockId);
4
Settle Trade
5
Atomically transfer locked balances between the counterparties. These are internal ledger movements - no on-chain token transfers occur.
6
const settlementId = ethers.utils.id("trade-001");

await custody.settleTrade(
  settlementId,
  maker,
  taker,
  commodityToken.address,  // base token
  usdc.address,             // quote token
  baseAmount,
  quoteAmount,
  true                      // makerIsBuyer
);
For high-throughput scenarios, use batchSettleTrades to settle multiple trades in one transaction. Size batches based on your target chain’s block gas limit. The gas guard stops processing if remaining gas drops below 80,000, so always check the BatchSettled event’s settledCount against totalSubmitted and retry any remaining settlements.

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Liquidation Flows

Two paths exist for settling liquidated collateral received from a lending market.

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Path A: Internal Buyer

The buyer already has USDC in custody. Tokens move between internal balances and USDC is transferred on-chain to the router. 
await custody.settleLiquidationWithBuyer(
  liquidationId,
  buyerAddress,
  tokenAmount,
  usdcAmount
);
Partial fills are supported. The liquidation remains open until the full token amount is matched. Check getLiquidation(liquidationId) to see the remaining amount.

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Path B: External Sale

The operator sells tokens through an external venue, then provides USDC proceeds. The commodity token enforces compliance during the on-chain transfer to the external buyer. 
// Operator approves USDC to custody
await usdc.approve(custody.address, usdcReceived);

await custody.settleLiquidation(
  liquidationId,
  usdcReceived,
  externalBuyerAddress  // receives the commodity tokens
);
Both paths notify the lending market via ILendingMarket.receiveLiquidationProceeds. If the callback reverts, settlement still completes. Monitor LiquidationSettled and LiquidationSoldToBuyer events for reconciliation.

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Priority Trade Flow

For liquidating tokens already held in a user’s custody balance (not received via the router): 
// 1. Freeze user to prevent withdrawal front-running
await custody.freezeUser(liquidatedUser);

// 2. Lock the user's tokens
await custody.lockBalance(liquidatedUser, commodityToken.address, amount, lockId);

// 3. Settle with a buyer
await custody.settlePriorityTrade(
  settlementId,
  liquidatedUser,
  buyer,
  commodityToken.address,
  usdc.address,
  baseAmount,
  quoteAmount
);

// 4. Unfreeze the user
await custody.unfreezeUser(liquidatedUser);
On L1 Ethereum, front-running between these steps is possible. Deploy on an L2 or use a private mempool for liquidation transactions.

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Listening to Events

Index these events for your backend, matching engine, and reporting systems: 
// Custody operations
custody.on("Deposited", (user, token, amount, newBalance) => { /* ... */ });
custody.on("Withdrawn", (user, token, amount) => { /* ... */ });

// Trade lifecycle
custody.on("BalanceLocked", (user, token, amount, lockId) => { /* ... */ });
custody.on("TradeSettled", (settlementId, maker, taker, baseToken, quoteToken, baseAmount, quoteAmount) => { /* ... */ });
custody.on("BatchSettled", (batchId, settledCount, totalSubmitted) => { /* ... */ });

// Liquidation
custody.on("LiquidationReceived", (liquidationId, token, amount, debtOwed, borrower, lendingMarket) => { /* ... */ });
custody.on("LiquidationSettled", (liquidationId, usdcReceived, tokenRecipient) => { /* ... */ });
custody.on("LiquidationSoldToBuyer", (liquidationId, buyer, tokenAmount, usdcAmount, fullyFilled) => { /* ... */ });

// Emergency controls
custody.on("UserFrozen", (user, operator) => { /* ... */ });
custody.on("WithdrawalsPaused", (operator) => { /* ... */ });

// CRITICAL: also monitor commodity token compliance changes
commodityToken.on("TransferRestrictionModeUpdated", (oldMode, newMode) => {
  // Re-verify custody contract authorization under the new mode
});

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API Integration

If you are using Trusset’s API layer, custody balances and settlements are managed through the Stock Trading API groups (which serve both stock and commodity orderbooks). The API handles deposit orchestration, settlement submission, and balance queries without direct contract interaction. For direct contract integration (self-hosted or custom deployment), use standard ethers.js or viem patterns with the contract ABIs included in the license package.