Treasury Pays for Minting (TS/JS + Fetch)
An example of a CIP-68 mint where a central treasury wallet pays the transaction fees, using TypeScript or JavaScript.
This example requires several utility and configuration files. Create the following files in the same directory as your main script.
https://github.com/Cardano-Forge/anvil-api-examples/blob/main/utils/constant.ts
// See Authentication page for API key details.
export const X_API_KEY = "testnet_EyrkvCWDZqjkfLSe1pxaF0hXxUcByHEhHuXIBjt9";
export const NETWORK = "preprod";
export const API_URL = `https://${NETWORK}.api.ada-anvil.app/v2/services`;
export const HEADERS = {
"Content-Type": "application/json",
"x-api-key": X_API_KEY,
};
You will also need the shared utility functions, which you can find in the utils/shared.ts file in the examples repository.
https://github.com/Cardano-Forge/anvil-api-examples/blob/main/fetch-utxos-from-the-backend/utxos/blockfrost.ts
import { Buffer } from "node:buffer";
import {
TransactionUnspentOutput,
TransactionInput,
TransactionOutput,
TransactionHash,
MultiAsset,
Value,
Assets,
AssetName,
BigNum,
ScriptHash,
Address,
} from "npm:@emurgo/cardano-serialization-lib-nodejs";
export function hex_to_uint8(input: string): Uint8Array {
return new Uint8Array(Buffer.from(input, "hex"));
}
export function assets_to_value(
multi_asset: MultiAsset,
assets: Asset[],
): Value {
const qt = assets.find((asset) => asset.unit === "lovelace")?.quantity;
if (!qt) {
throw new Error("No lovelace found in the provided utxo");
}
const assets_to_add: Record<string, Assets> = {};
for (const asset of assets) {
if (asset.unit !== "lovelace") {
const policy_hex = asset.unit.slice(0, 56);
const asset_hex = hex_to_uint8(asset.unit.slice(56));
if (!assets_to_add[policy_hex]) {
assets_to_add[policy_hex] = Assets.new();
}
assets_to_add[policy_hex].insert(
AssetName.new(asset_hex),
BigNum.from_str(asset.quantity),
);
}
}
for (const key of Object.keys(assets_to_add)) {
multi_asset.insert(ScriptHash.from_hex(key), assets_to_add[key]);
}
return Value.new_with_assets(BigNum.from_str(qt), multi_asset);
}
export type Asset = {
unit: string;
quantity: string;
};
export type Utxo = {
address: string;
tx_hash: string;
output_index: number;
amount: Asset[];
block?: string;
data_hash?: string | null;
inline_datum?: string | null;
reference_script_hash?: string | null;
};
export async function getUtxos(
blockfrost_base_url: string,
blockfrost_api_key: string,
address: string,): Promise<string[]> {
const utxoHexList: string[] = [];
let page = 1;
// Loop through paginated results from Blockfrost
while (true) {
const res = await fetch(
`${blockfrost_base_url}/addresses/${address}/utxos?page=${page}`,
{
method: "GET",
headers: {
"Content-Type": "application/json",
Accept: "application/json",
project_id: blockfrost_api_key,
},
},
);
if (!res.ok) {
const errorText = await res.text();
throw new Error(
`Unable to get utxos for specified address. Status: ${res.status}, Response: ${errorText}`,
);
}
const pageUtxos: Utxo[] = await res.json();
// If the page is empty, we've fetched all UTXOs.
if (pageUtxos.length === 0) {
break;
}
// Convert UTXOs to array of CBOR hex strings
for (const utxo of pageUtxos) {
const multi_assets = MultiAsset.new();
const { tx_hash, output_index, amount, address } = utxo;
const txUnspentOutput = TransactionUnspentOutput.new(
TransactionInput.new(TransactionHash.from_hex(tx_hash), output_index),
TransactionOutput.new(
Address.from_bech32(address),
assets_to_value(multi_assets, amount),
),
);
utxoHexList.push(txUnspentOutput.to_hex());
}
page++;
}
return utxoHexList;
}
// Function to find CIP-68 reference token (label 100) UTXO dynamically from script address
export async function findReferenceTokenUTXO(
blockfrost_base_url: string,
blockfrost_api_key: string,
policyId: string,
baseAssetName: string,
scriptAddress: string,
): Promise<{ transaction_id: string; output_index: number }> {
// Fetch all UTXOs from script address
const response = await fetch(
`${blockfrost_base_url}/addresses/${scriptAddress}/utxos`,
{
method: "GET",
headers: {
"Content-Type": "application/json",
Accept: "application/json",
project_id: blockfrost_api_key,
},
},
);
if (!response.ok) {
const errorText = await response.text();
throw new Error(`Failed to fetch UTXOs: ${response.status} ${response.statusText}. Details: ${errorText}`);
}
const utxos: Utxo[] = await response.json();
// CIP-68 reference token has label 100 (full CIP-67 format: 000643b0)
const referenceTokenLabel = "000643b0"; // 100 with CRC-8 checksum per CIP-67
const expectedAssetUnit = `${policyId}${referenceTokenLabel}${Buffer.from(baseAssetName).toString("hex")}`;
// Find UTXO containing the reference token
for (const utxo of utxos) {
for (const asset of utxo.amount) {
if (asset.unit === expectedAssetUnit && parseInt(asset.quantity) > 0) {
return {
transaction_id: utxo.tx_hash,
output_index: utxo.output_index,
};
}
}
}
throw new Error(
`â Reference token not found at script address.\n` +
`Expected asset: ${expectedAssetUnit}\n` +
`Policy ID: ${policyId}\n` +
`Base asset name: ${baseAssetName}\n` +
`Script address: ${scriptAddress}`
);
}
// Function to find CIP-68 user token (label 222) UTXO dynamically from customer's wallet
export async function findUserTokenUTXO(
blockfrost_base_url: string,
blockfrost_api_key: string,
policyId: string,
baseAssetName: string,
customerAddress: string
): Promise<{ transaction_id: string; output_index: number }> {
// Fetch all UTXOs from customer's address
const response = await fetch(
`${blockfrost_base_url}/addresses/${customerAddress}/utxos`,
{
method: "GET",
headers: {
"Content-Type": "application/json",
Accept: "application/json",
project_id: blockfrost_api_key,
},
},
);
if (!response.ok) {
const errorText = await response.text();
throw new Error(`Failed to fetch UTXOs: ${response.status} ${response.statusText}. Details: ${errorText}`);
}
const utxos: Utxo[] = await response.json();
// CIP-68 user token has label 222 (full CIP-67 format: 000de140)
const userTokenLabel = "000de140"; // 222 with CRC-8 checksum per CIP-67
const expectedAssetUnit = `${policyId}${userTokenLabel}${Buffer.from(baseAssetName).toString("hex")}`;
// Find UTXO containing the user token
for (const utxo of utxos) {
for (const asset of utxo.amount) {
if (asset.unit === expectedAssetUnit && parseInt(asset.quantity) > 0) {
return {
transaction_id: utxo.tx_hash,
output_index: utxo.output_index,
};
}
}
}
throw new Error(
`â User token not found in wallet.\n` +
`Expected asset: ${expectedAssetUnit}\n` +
`Policy ID: ${policyId}\n` +
`Base asset name: ${baseAssetName}\n` +
`Customer address: ${customerAddress}`
);
}
Now, you can run the main script:
https://github.com/Cardano-Forge/anvil-api-examples/blob/main/documentation-references/cip68-treasury-pays.ts
/**
* CIP-68 Treasury Pays Example
*
* This script demonstrates how to mint CIP-68 tokens (a reference token and a user token)
* where the transaction fees are paid from a designated treasury wallet.
*
* This involves:
* 1. Loading customer, treasury, policy, and metadata manager wallets.
* 2. Creating a time-locked native script signed by the policy wallet.
* 3. Defining the asset metadata for both the reference (label 100) and user (label 222) tokens.
* 4. Fetching UTXOs from the treasury wallet to cover transaction fees.
* 5. Building the transaction payload with the mint operation and preloaded native script.
* 6. Signing the transaction with both the treasury and metadata manager private keys.
* 7. Submitting the transaction to the Anvil API.
*
* Required environment variables: BLOCKFROST_PROJECT_ID, ANVIL_API_KEY
* Prerequisite: deno run --allow-all --env-file=.env cip68-treasury-pays.ts
*/
import { Buffer } from "node:buffer";
import {
FixedTransaction,
PrivateKey,
} from "npm:@emurgo/[email protected]";
import {
timeToSlot,
getKeyhash,
createNativeScript,
} from "../utils/shared.ts";
import { API_URL, HEADERS } from "../utils/constant.ts";
import { getUtxos } from "../fetch-utxos-from-the-backend/utxos/blockfrost.ts";
// 1. Load wallets
const customerWallet = JSON.parse(Deno.readTextFileSync("wallet-customer.json"));
const treasuryWallet = JSON.parse(Deno.readTextFileSync("wallet-treasury.json"));
const policyWallet = JSON.parse(Deno.readTextFileSync("wallet-policy.json"));
const metaManagerWallet = JSON.parse(Deno.readTextFileSync("wallet-meta-manager.json"));
// 2. Create native script (expires 2026-01-01, signed by policy wallet)
const counter = new Date().getTime();
const slot = await timeToSlot(new Date("2026-01-01"));
const keyhash = await getKeyhash(policyWallet.base_address_preprod);
if (!keyhash) {
throw new Error("Unable to get key hash for policy wallet.");
}
const nativeScript = await createNativeScript(keyhash, slot);
// 3. Define assets to be minted
const assets = [
{
// Reference Token (label 100) -> sent to Metadata Manager Address
version: "cip68",
assetName: { name: `anvilapicip68_${counter}`, format: "utf8", label: 100 },
metadata: {
name: `anvil-api-${counter}`,
image: "ipfs://QmQZJ1J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J",
mediaType: "image/png",
description: "Anvil API CIP-68 Treasury Pays Example",
},
policyId: nativeScript.hash,
quantity: 1,
destAddress: metaManagerWallet.base_address_preprod,
},
{
// User Token (label 222) -> sent to Customer Address
version: "cip68",
assetName: { name: `anvilapicip68_${counter}`, format: "utf8", label: 222 },
policyId: nativeScript.hash,
quantity: 1,
destAddress: customerWallet.base_address_preprod,
},
];
// 4. Get UTXOs from the treasury wallet
const BLOCKFROST_PROJECT_ID = Deno.env.get("BLOCKFROST_PROJECT_ID");
if (!BLOCKFROST_PROJECT_ID) {
throw new Error("Missing BLOCKFROST_PROJECT_ID env var");
}
const utxos = await getUtxos(
"https://cardano-preprod.blockfrost.io/api/v0",
BLOCKFROST_PROJECT_ID,
treasuryWallet.base_address_preprod,
);
console.log(`Found ${utxos.length} UTXOs in treasury wallet.`);
// 5. Build the transaction payload
const buildBody = {
changeAddress: treasuryWallet.base_address_preprod,
utxos,
mint: assets,
preloadedScripts: [nativeScript],
};
console.log("Build Body: ", buildBody);
// 6. Build the transaction
const buildResponse = await fetch(`${API_URL}/transactions/build`, {
method: "POST",
body: JSON.stringify(buildBody),
headers: HEADERS,
});
if (!buildResponse.ok) {
throw new Error(`Failed to build transaction: ${await buildResponse.text()}`);
}
const buildJson = await buildResponse.json();
console.log("Build Output:", buildJson);
// 7. Sign the transaction
const transaction = FixedTransaction.from_bytes(Buffer.from(buildJson.complete, "hex"));
// Sign with Treasury wallet (pays for the transaction)
transaction.sign_and_add_vkey_signature(PrivateKey.from_bech32(treasuryWallet.skey));
// Sign with Metadata Manager wallet (controls the reference token)
transaction.sign_and_add_vkey_signature(PrivateKey.from_bech32(policyWallet.skey));
// 8. Submit the transaction
const submitResponse = await fetch(`${API_URL}/transactions/submit`, {
method: "POST",
body: JSON.stringify({
transaction: transaction.to_hex(),
}),
headers: HEADERS,
});
const submitJson = await submitResponse.json();
if (!submitResponse.ok) {
console.error("Submission failed. Response:", submitJson);
throw new Error(`Failed to submit transaction: ${submitResponse.statusText}`);
}
console.log("Submitted Transaction:", JSON.stringify(submitJson, null, 2));
/*
Sample Output
Found 3 UTXOs in treasury wallet.
Build Body: {
changeAddress: "addr_test1qpxpar5s94wv6n76jvmvkr8uhnrflge6fatjzlkuujw3m33mk0alnas44ptzrkqqp3kdhplmcwys5mlht5w6seefrtls2r748e",
utxos: [
"82825820cbdd371aca5fef27267d5a41d9af6c6d9c9ba46b16aa5501f6fae91d3415a1f700825839004c1e8e902d5ccd4fda9336cb0cfcbcc69fa33a4f57217edce49d1dc63bb3fbf9f615a85621d8000c6cdb87fbc3890a6ff75d1da867291aff1a05f5e100",
"82825820f3c3344a570042a0ad5753bd6af8a6ff360dbc41ea35c77f6502da89427efc9c00825839004c1e8e902d5ccd4fda9336cb0cfcbcc69fa33a4f57217edce49d1dc63bb3fbf9f615a85621d8000c6cdb87fbc3890a6ff75d1da867291aff1a01312d00",
"828258203bbfdc451b2d12a3388146113b9411da603c205a835579a6e1397e696e04f0df02825839004c1e8e902d5ccd4fda9336cb0cfcbcc69fa33a4f57217edce49d1dc63bb3fbf9f615a85621d8000c6cdb87fbc3890a6ff75d1da867291aff821a0979d543a3581c38fdf893232baf9703e2f051ff9083a2756063c8bce3d80eb8d5eb3fa148000de1407465737401581c5e3817eacf8b6c393307fa61b00d546678e24414380dc7a2d879bc78a148000de1407465737401581cf8e024681ee83f54bd5f9a033464168f619970289017a9f53454d950a148000de1407465737401"
],
mint: [
{
version: "cip68",
assetName: {
name: "anvilapicip68_1752704257434",
format: "utf8",
label: 100
},
metadata: {
name: "anvil-api-1752704257434",
image: "ipfs://QmQZJ1J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J3J",
mediaType: "image/png",
description: "Anvil API CIP-68 Treasury Pays Example"
},
policyId: "4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfb",
quantity: 1,
destAddress: "addr_test1qz7jcka6zwj0tz52rl73te7y7avl2ckzmkfguwl42h728jeqzph40hhsxq32p2t4r3qcnhsrk9nnq5m2yv04dhuf3hfsuqphqk"
},
{
version: "cip68",
assetName: {
name: "anvilapicip68_1752704257434",
format: "utf8",
label: 222
},
policyId: "4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfb",
quantity: 1,
destAddress: "addr_test1qqwadht4defe0cqem6a56ytwz96g4y7j7z0a02y5aj8c4unm5k2xfvhpn4kukwhsfakq22dy94yf9y8nt9dddzpkmuys4r5q8h"
}
],
preloadedScripts: [
{
type: "simple",
script: { type: "all", scripts: [ [Object], [Object] ] },
hash: "4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfb"
}
]
}
Build Output: {
hash: "6689bd7030901e036490e510d95f6535c7717345fe8a5541c3f6efe5efa5d65c",
complete: "84a700d90102818258203bbfdc451b2d12a3388146113b9411da603c205a835579a6e1397e696e04f0df02018483583900bd2c5bba13a4f58a8a1ffd15e7c4f759f562c2dd928e3bf555fca3cb20106f57def03022a0a9751c4189de03b16730536a231f56df898dd3821a00157084a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba1581f000643b0616e76696c61706963697036385f3137353237303432353734333401582080cbf5aab266792d95a836241f88b8a9e4e4e58f897884343f01dcbf57529f8f825839001dd6dd756e5397e019debb4d116e11748a93d2f09fd7a894ec8f8af27ba59464b2e19d6dcb3af04f6c0529a42d489290f3595ad68836df09821a00133418a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba1581f000de140616e76696c61706963697036385f313735323730343235373433340182583900e4c0e5e76be5cf9ea49b889cb6e54baed815859c35b2d9fe84b04b222435fcd97a6b0717fbd3658537d3dfd3360267449dcd2cd4de5928e01a0020ce70825839004c1e8e902d5ccd4fda9336cb0cfcbcc69fa33a4f57217edce49d1dc63bb3fbf9f615a85621d8000c6cdb87fbc3890a6ff75d1da867291aff821a092ce9faa3581c38fdf893232baf9703e2f051ff9083a2756063c8bce3d80eb8d5eb3fa148000de1407465737401581c5e3817eacf8b6c393307fa61b00d546678e24414380dc7a2d879bc78a148000de1407465737401581cf8e024681ee83f54bd5f9a033464168f619970289017a9f53454d950a148000de1407465737401021a0003783d031a05c88894081a05c86c7409a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba2581f000643b0616e76696c61706963697036385f3137353237303432353734333401581f000de140616e76696c61706963697036385f31373532373034323537343334010b58204587ac46d0a5802afe974301ec122e228c20b19fbd15ba26eaf9c1770d687d0da201d90102818201828200581c3910f0db63599cd9cb1484d5591491629470761a89cde0473e4b94f682051a06a6008004d901029fd8799fa4446e616d6557616e76696c2d6170692d3137353237303432353734333445696d6167655830697066733a2f2f516d515a4a314a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a496d656469615479706549696d6167652f706e674b6465736372697074696f6e5826416e76696c20415049204349502d36382054726561737572792050617973204578616d706c6501fffff5f6",
stripped: "84a700d90102818258203bbfdc451b2d12a3388146113b9411da603c205a835579a6e1397e696e04f0df02018483583900bd2c5bba13a4f58a8a1ffd15e7c4f759f562c2dd928e3bf555fca3cb20106f57def03022a0a9751c4189de03b16730536a231f56df898dd3821a00157084a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba1581f000643b0616e76696c61706963697036385f3137353237303432353734333401582080cbf5aab266792d95a836241f88b8a9e4e4e58f897884343f01dcbf57529f8f825839001dd6dd756e5397e019debb4d116e11748a93d2f09fd7a894ec8f8af27ba59464b2e19d6dcb3af04f6c0529a42d489290f3595ad68836df09821a00133418a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba1581f000de140616e76696c61706963697036385f313735323730343235373433340182583900e4c0e5e76be5cf9ea49b889cb6e54baed815859c35b2d9fe84b04b222435fcd97a6b0717fbd3658537d3dfd3360267449dcd2cd4de5928e01a0020ce70825839004c1e8e902d5ccd4fda9336cb0cfcbcc69fa33a4f57217edce49d1dc63bb3fbf9f615a85621d8000c6cdb87fbc3890a6ff75d1da867291aff821a092ce9faa3581c38fdf893232baf9703e2f051ff9083a2756063c8bce3d80eb8d5eb3fa148000de1407465737401581c5e3817eacf8b6c393307fa61b00d546678e24414380dc7a2d879bc78a148000de1407465737401581cf8e024681ee83f54bd5f9a033464168f619970289017a9f53454d950a148000de1407465737401021a0003783d031a05c88894081a05c86c7409a1581c4d5bd6249f0d9e4b2762ce334e2973dc7fd414ec1e08b4b0c2159bfba2581f000643b0616e76696c61706963697036385f3137353237303432353734333401581f000de140616e76696c61706963697036385f31373532373034323537343334010b58204587ac46d0a5802afe974301ec122e228c20b19fbd15ba26eaf9c1770d687d0da0f5f6",
witnessSet: "a201d90102818201828200581c3910f0db63599cd9cb1484d5591491629470761a89cde0473e4b94f682051a06a6008004d901029fd8799fa4446e616d6557616e76696c2d6170692d3137353237303432353734333445696d6167655830697066733a2f2f516d515a4a314a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a334a496d656469615479706549696d6167652f706e674b6465736372697074696f6e5826416e76696c20415049204349502d36382054726561737572792050617973204578616d706c6501ffff"
}
Submitted Transaction: {
"txHash": "6689bd7030901e036490e510d95f6535c7717345fe8a5541c3f6efe5efa5d65c"
}
*/ Learn More
For a step-by-step explanation, see the Mint a CIP-68 NFT Guide.
Last updated
Was this helpful?