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Transactions

Your first transaction​

A couple of fundamentals to remember are that in Cardano's eUTxO model, a transaction can consume one or more UTxOs as inputs, create one or more UTxOs as outputs, and must be balanced (sum of inputs = sum of outputs + fees).

1. Build​

Let's create a simple transaction where we send 5 ada to two recipients each:

const tx = await lucid
  .newTx()
  .pay.ToAddress("addr_testa...", { lovelace: 5000000n })
  .pay.ToAddress("addr_testb...", { lovelace: 5000000n })
  .complete();
note

To balance the transaction and initiate coin selection, transactions always need to end with .complete()

2. Sign​

const signedTx = await tx.sign.withWallet().complete();

You could also choose to sign the transaction with a private key:

const signedTx = await tx.sign.withPrivateKey(privateKey).complete();

3. Submit​

Lastly we submit the transaction:

const txHash = await signedTx.submit();
console.log(txHash);
note

The wallet selection methods we discussed in the previous section should be implemented before building the transaction.

Putting everything together​

import { Lucid, Blockfrost } from "@lucid-evolution/lucid";

// Initialize Lucid with a provider
const lucid = await Lucid(
  new Blockfrost("https://cardano-preprod.blockfrost.io/api/v0", "<projectId>"),
  "Preprod"
);

// Select a wallet for signing - in this case we're using a private key
lucid.selectWallet.fromPrivateKey(privateKey);

// Build, sign and submit transaction
const tx = await lucid
  .newTx()
  .pay.ToAddress("addr_testa...", { lovelace: 5000000n }) // Pay 5 ada to addr_testa
  .complete(); // Balances the transaction and initiates coin selection

const signedTx = await tx.sign.withWallet().complete();
const txHash = await signedTx.submit();
console.log(txHash);

You want to learn more?​

Next Steps​

Explore the following sections to learn more about Lucid Evolution:

  • Under the hood - Understand how Evolution library works
  • Deep dives - Follow this series in order to step-by-step understand how to build your own off-chain code for different/advanced use cases

Video Tutorial​

Resources​

You now have all you need to start playing around with Lucid Evolution. If you have any questions, please refer to the library's Discord community.