Create, sign, and submit transactions on your Yaci devnet. Learn to build simple transfers and complex smart contract interactions.

Overview

This guide shows you how to build and submit transactions on a Yaci devnet using Mesh SDK. The same code works on both local and hosted devnets - only the provider URL changes.

What you will learn

Connect YaciProvider to your devnet
Fetch UTxOs and protocol parameters
Build and submit basic ADA transfers
Handle transaction errors

Prerequisites

Before building transactions, ensure you have:

Requirement	Description
Yaci devnet	Running locally or using Mesh's hosted devnet
Funded wallet	Address with test ADA (use `topup` command)
Mesh SDK	`@meshsdk/core` package installed

npm install @meshsdk/core

Quick start

Send 1 ADA to another address:

import { YaciProvider, MeshTxBuilder } from "@meshsdk/core";
import { MeshCardanoHeadlessWallet, AddressType } from "@meshsdk/wallet";

// Connect to devnet
const provider = new YaciProvider("https://yaci-node.meshjs.dev/api/v1/");

// Create wallet
const wallet = await MeshCardanoHeadlessWallet.fromMnemonic({
  networkId: 0,
  walletAddressType: AddressType.Base,
  fetcher: provider,
  submitter: provider,
  mnemonic: "your mnemonic words here".split(" "),
});

// Build and submit transaction
const utxos = await wallet.getUtxosMesh();
const changeAddress = await wallet.getChangeAddressBech32();

const txBuilder = new MeshTxBuilder({ fetcher: provider });

const unsignedTx = await txBuilder
  .txOut("addr_test1...", [{ unit: "lovelace", quantity: "1000000" }])
  .changeAddress(changeAddress)
  .selectUtxosFrom(utxos)
  .complete();

const signedTx = await wallet.signTx(unsignedTx, false);
const txHash = await wallet.submitTx(signedTx);

console.log("Transaction submitted:", txHash);

Setup

Connect to hosted devnet

import { YaciProvider } from "@meshsdk/core";

// Default: Mesh hosted devnet
const provider = new YaciProvider();

// Or explicit URL
const providerExplicit = new YaciProvider("https://yaci-node.meshjs.dev/api/v1/");

Connect to local devnet

import { YaciProvider } from "@meshsdk/core";

// Local Yaci DevKit
const provider = new YaciProvider("http://localhost:8080/api/v1/");

YaciProvider constructor

const provider = new YaciProvider(
  yaciUrl?: string,    // Yaci Store API URL
  adminUrl?: string    // Optional admin API for advanced operations
);

API reference

Fetch UTxOs

Get all UTxOs for an address:

import { YaciProvider } from "@meshsdk/core";

const provider = new YaciProvider("https://yaci-node.meshjs.dev/api/v1/");

const utxos = await provider.fetchAddressUTxOs(
  "addr_test1qpvx0sacufuypa2k4sngk7q40zc5c4npl337uusdh64kv0uafhxhu32dys6pvn6wlw8dav6cmp4pmtv7cc3yel9uu0nq93swx9"
);

console.log("UTxOs found:", utxos.length);
utxos.forEach((utxo) => {
  console.log(`  ${utxo.input.txHash}#${utxo.input.outputIndex}`);
});

Fetch protocol parameters

Get current protocol parameters for transaction building:

import { YaciProvider } from "@meshsdk/core";

const provider = new YaciProvider();

const params = await provider.fetchProtocolParameters();
console.log("Min fee coefficient:", params.minFeeA);
console.log("Min fee constant:", params.minFeeB);

Build a basic transaction

Step 1: Set up wallet and provider

import { YaciProvider, MeshTxBuilder } from "@meshsdk/core";
import { MeshCardanoHeadlessWallet, AddressType } from "@meshsdk/wallet";

const provider = new YaciProvider();

const wallet = await MeshCardanoHeadlessWallet.fromMnemonic({
  networkId: 0, // testnet
  walletAddressType: AddressType.Base,
  fetcher: provider,
  submitter: provider,
  mnemonic: [
    "test", "test", "test", "test", "test", "test",
    "test", "test", "test", "test", "test", "test",
    "test", "test", "test", "test", "test", "test",
    "test", "test", "test", "test", "test", "sauce"
  ],
});

Step 2: Get UTxOs and addresses

const utxos = await wallet.getUtxosMesh();
const changeAddress = await wallet.getChangeAddressBech32();

console.log("Available UTxOs:", utxos.length);
console.log("Change address:", changeAddress);

Step 3: Build the transaction

const txBuilder = new MeshTxBuilder({
  fetcher: provider,
});

const recipientAddress = "addr_test1qpvx0sacufuypa2k4sngk7q40zc5c4npl337uusdh64kv0uafhxhu32dys6pvn6wlw8dav6cmp4pmtv7cc3yel9uu0nq93swx9";

const unsignedTx = await txBuilder
  .txOut(recipientAddress, [{ unit: "lovelace", quantity: "1000000" }])
  .changeAddress(changeAddress)
  .selectUtxosFrom(utxos)
  .complete();

Step 4: Sign and submit

const signedTx = await wallet.signTx(unsignedTx, false);
const txHash = await wallet.submitTx(signedTx);

console.log("Transaction hash:", txHash);

Complete example

Full working example with error handling:

import { YaciProvider, MeshTxBuilder } from "@meshsdk/core";
import { MeshCardanoHeadlessWallet, AddressType } from "@meshsdk/wallet";

async function sendAda() {
  // Configuration
  const YACI_URL = "https://yaci-node.meshjs.dev/api/v1/";
  const MNEMONIC = "test test test test test test test test test test test test test test test test test test test test test test test sauce";
  const RECIPIENT = "addr_test1qpvx0sacufuypa2k4sngk7q40zc5c4npl337uusdh64kv0uafhxhu32dys6pvn6wlw8dav6cmp4pmtv7cc3yel9uu0nq93swx9";
  const AMOUNT = "5000000"; // 5 ADA in lovelace

  // Initialize provider
  const provider = new YaciProvider(YACI_URL);

  // Verify connection
  try {
    const params = await provider.fetchProtocolParameters();
    console.log("Connected to Yaci devnet");
  } catch (error) {
    console.error("Failed to connect to devnet:", error);
    return;
  }

  // Initialize wallet
  const wallet = await MeshCardanoHeadlessWallet.fromMnemonic({
    networkId: 0,
    walletAddressType: AddressType.Base,
    fetcher: provider,
    submitter: provider,
    mnemonic: MNEMONIC.split(" "),
  });

  // Get wallet state
  const changeAddress = await wallet.getChangeAddressBech32();
  const utxos = await wallet.getUtxosMesh();

  console.log("Sender address:", changeAddress);
  console.log("Available UTxOs:", utxos.length);

  if (utxos.length === 0) {
    console.error("No UTxOs available. Fund the wallet first:");
    console.log(`  devnet:default> topup ${changeAddress} 1000`);
    return;
  }

  // Calculate total available
  const totalLovelace = utxos.reduce((sum, utxo) => {
    const lovelace = utxo.output.amount.find((a) => a.unit === "lovelace");
    return sum + BigInt(lovelace?.quantity || 0);
  }, BigInt(0));

  console.log("Total available:", totalLovelace.toString(), "lovelace");

  // Build transaction
  const txBuilder = new MeshTxBuilder({
    fetcher: provider,
  });

  try {
    const unsignedTx = await txBuilder
      .txOut(RECIPIENT, [{ unit: "lovelace", quantity: AMOUNT }])
      .changeAddress(changeAddress)
      .selectUtxosFrom(utxos)
      .complete();

    console.log("Transaction built successfully");

    // Sign transaction
    const signedTx = await wallet.signTx(unsignedTx, false);
    console.log("Transaction signed");

    // Submit transaction
    const txHash = await wallet.submitTx(signedTx);
    console.log("Transaction submitted!");
    console.log("Transaction hash:", txHash);

    // Verify submission
    console.log("\nVerify on Yaci Viewer: http://localhost:5173");
    console.log(`Or fetch UTxOs for recipient to confirm receipt`);

  } catch (error) {
    console.error("Transaction failed:", error);
  }
}

sendAda().catch(console.error);

Fund your wallet

Before running transactions, fund your wallet using yaci-cli:

devnet:default> topup addr_test1qryvgass5dsrf2kxl3vgfz76uhp83kv5lagzcp29tcana68ca5aqa6swlq6llfamln09tal7n5kvt4275ckwedpt4v7q48uhex 1000

Then verify the funding:

const utxos = await provider.fetchAddressUTxOs(address);
console.log("Funded UTxOs:", utxos);

Transaction patterns

Send to multiple recipients

const unsignedTx = await txBuilder
  .txOut(recipient1, [{ unit: "lovelace", quantity: "1000000" }])
  .txOut(recipient2, [{ unit: "lovelace", quantity: "2000000" }])
  .txOut(recipient3, [{ unit: "lovelace", quantity: "3000000" }])
  .changeAddress(changeAddress)
  .selectUtxosFrom(utxos)
  .complete();

Send native tokens

const unsignedTx = await txBuilder
  .txOut(recipient, [
    { unit: "lovelace", quantity: "2000000" },
    { unit: "<policy_id><asset_name>", quantity: "100" }
  ])
  .changeAddress(changeAddress)
  .selectUtxosFrom(utxos)
  .complete();

Set explicit fee

const unsignedTx = await txBuilder
  .txOut(recipient, [{ unit: "lovelace", quantity: "1000000" }])
  .changeAddress(changeAddress)
  .selectUtxosFrom(utxos)
  .setFee("200000") // Explicit 0.2 ADA fee
  .complete();

Troubleshooting

"No UTxOs available"

Fund your wallet using the devnet topup command:

devnet:default> topup <your-address> 1000

"Insufficient funds"

Check your available balance:

const utxos = await wallet.getUtxosMesh();
const total = utxos.reduce((sum, u) => {
  const lovelace = u.output.amount.find((a) => a.unit === "lovelace");
  return sum + BigInt(lovelace?.quantity || 0);
}, BigInt(0));
console.log("Available:", total.toString(), "lovelace");

"Connection refused"

Verify the devnet is running:

curl http://localhost:8080/api/v1/protocol-parameters

For hosted devnet:

curl https://yaci-node.meshjs.dev/api/v1/protocol-parameters

Transaction not appearing

Wait a few seconds for the next block, then check:

// Wait for block production
await new Promise((resolve) => setTimeout(resolve, 5000));

// Check recipient UTxOs
const recipientUtxos = await provider.fetchAddressUTxOs(recipientAddress);
console.log("Recipient UTxOs:", recipientUtxos);

Getting Started - Install and configure Yaci DevKit
Yaci Overview - Introduction to Yaci
MeshTxBuilder - Full transaction builder documentation
Cardano Providers - All available blockchain providers

Build Transactions on Yaci