Burn & Mint Token

Deploy a cross-chain ERC20 that burns on the source chain and mints on the destination. Total supply stays constant — tokens are destroyed on one side and created on the other.

Use this when you control the token. If you need to bridge a token you don't control (like USDC), see Lock & Release.

Choosing a Bridge Pattern

Pattern	Token control	Liquidity needed	Destination token
Burn & Mint	You control it	No	Same token (minted)
Lock & Mint	You don't control it	No	Wrapped/synthetic version
Lock & Release	You don't control it	Yes, pre-funded	Original token

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Prerequisites

• A working Hardhat project with VIA contracts — complete the Hello World guide first
• Testnet tokens on two chains — see Testnet Tokens

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Step 1: Copy the Contract

Copy VIAMintBurnTokenMinimal.sol from the Contract Source page into your contracts/ directory. See the full reference for API details.

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Step 2: Deploy

Mint the entire initial supply on one chain only — the destination deployment starts at zero and only receives tokens when they're bridged in. This is what keeps total supply constant across chains.

Create scripts/deploy-token.ts:

import { ethers } from "hardhat";

// Mint the full supply on the source chain (Sepolia).
// Set this to 0 before deploying to the destination chain (Fuji).
const INITIAL_SUPPLY = 1000000;

async function main() {
  const Token = await ethers.getContractFactory("VIAMintBurnTokenMinimal");
  const token = await Token.deploy("My Token", "MTK", INITIAL_SUPPLY);
  await token.waitForDeployment();
  console.log("Deployed to:", await token.getAddress());
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Deploy to Sepolia with the full supply:

npx hardhat run scripts/deploy-token.ts --network sepolia

Then change INITIAL_SUPPLY to 0 and deploy to Fuji:

npx hardhat run scripts/deploy-token.ts --network fuji

Save both addresses.

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Step 3: Configure

Same pattern as Hello World — Step 7. On each chain, call setMessageGateway() and setMessageEndpoints() pointing at the peer contract.

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Step 4: Bridge Tokens

Create scripts/bridge.ts:

import { ethers } from "hardhat";

const TOKEN_ADDRESS = "";       // your contract on source chain
const DEST_CHAIN_ID = 43113;    // Fuji
const RECIPIENT = "";           // recipient address on destination chain
const AMOUNT = ethers.parseEther("100");

async function main() {
  const token = await ethers.getContractAt("VIAMintBurnTokenMinimal", TOKEN_ADDRESS);

  const recipientBytes32 = ethers.zeroPadValue(RECIPIENT, 32);

  console.log("Bridging", ethers.formatEther(AMOUNT), "tokens...");
  const tx = await token.bridge(recipientBytes32, DEST_CHAIN_ID, AMOUNT);
  await tx.wait();
  console.log("TX:", tx.hash);
  console.log("Tokens burned. Wait 1-5 minutes for mint on destination.");
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

npx hardhat run scripts/bridge.ts --network sepolia

Delivery fees

On testnets, message delivery is currently free — no value needs to be attached to bridge(). On mainnet, delivery fees may apply; see Fees & Gas.

caution

Burns are irreversible. If destination messageProcess() fails, source tokens are already burned. Recovery requires the owner to manually mint replacement tokens.

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Next Steps

• Lock & Release Token — bridge tokens you don't control
• Contract Source — ViaIntegrationV1 and reference implementations