Burning Native Tokens

This guide demonstrates how to burn native tokens in an open Hydra Head using a CIP-30 wallet and KuberHydraApiProvider.

When to use this flow

Use token burn when you need to reduce total circulating supply for a policy, invalidate temporary in-app assets, or clean up test assets after scenario runs.

Prerequisites

• Node.js environment
• libcardano and libcardano-wallet installed
• An active Hydra Head in Open state
• A wallet that currently holds the token you want to burn
• The same mint policy used when the token was created

Example: Burn 1 Token1

import { KuberHydraApiProvider } from "kuber-client";
import { CardanoKeyAsync } from "libcardano";
import { ShelleyWallet, SimpleCip30Wallet } from "libcardano-wallet";
import { readFileSync } from "fs";

async function runBurnNativeTokensExample() {
  const hydra = new KuberHydraApiProvider("http://localhost:8082");

  const signingKey = await CardanoKeyAsync.fromCardanoCliJson(
    JSON.parse(
      readFileSync(
        process.env.HOME + "/.cardano/preview/hydra-0/credentials/funds.sk",
        "utf-8",
      ),
    ),
  );

  const shelleyWallet = new ShelleyWallet(signingKey);
  const wallet = new SimpleCip30Wallet(hydra, hydra, shelleyWallet, 0);
  const walletAddress = (await wallet.getChangeAddress()).toBech32();

  const headState = await hydra.queryHeadState();
  if (headState.state !== "Open") {
    throw new Error(`Hydra head is ${headState.state}. Expected Open.`);
  }

  // Negative amount burns assets under the policy script.
  const burnTx = {
    mint: [
      {
        script: {
          type: "sig",
          keyHash: shelleyWallet.paymentKey.pkh.toString("hex"),
        },
        amount: {
          Token1: -1,
        },
      },
    ],
    changeAddress: walletAddress,
  };

  const result = await hydra.buildAndSubmitWithWallet(wallet, burnTx);
  console.log("Burn transaction submitted:", result.transaction.toBytes().toString("hex"));
}

runBurnNativeTokensExample().catch((err) => {
  console.error("Burn flow failed:", err);
});

Verify the burn

1. Query wallet UTxOs before and after the burn.
2. Confirm token quantity decreased by the expected amount.
3. Confirm no policy mismatch error occurred.

Common issues

• ValueNotConservedUTxO: burn amount is larger than wallet token balance.
• Script witness failure: policy script/key hash does not match minted asset policy.
• Head not open: call this flow only after commit + head open.