Sui Programmable Transaction Basics

This example starts by constructing a transaction to send SUI. To construct transactions, import the Transaction class and construct it:

import { Transaction } from '@mysten/sui/transactions';
 
const tx = new Transaction();

You can then add transactions to the transaction .

// create a new coin with balance 100, based on the coins used as gas payment
// you can define any balance here
const [coin] = tx.splitCoins(tx.gas, [100]);
 
// transfer the split coin to a specific address
tx.transferObjects([coin], '0xSomeSuiAddress');

You can attach multiple transactions of the same type to a transaction, as well. For example, to get a list of transfers and iterate over them to transfer coins to each of them:

interface Transfer {
	to: string;
	amount: number;
}
 
// procure a list of some Sui transfers to make
const transfers: Transfer[] = getTransfers();
 
const tx = new Transaction();
 
// first, split the gas coin into multiple coins
const coins = tx.splitCoins(
	tx.gas,
	transfers.map((transfer) => transfer.amount),
);
 
// next, create a transfer transaction for each coin
transfers.forEach((transfer, index) => {
	tx.transferObjects([coins[index]], transfer.to);
});

After you have the transaction defined, you can directly execute it with a signer using signAndExecuteTransaction.

client.signAndExecuteTransaction({ signer: keypair, transaction: tx });

Transactions

Programmable Transactions have two key concepts: inputs and transactions.

Transactions are steps of execution in the transaction. Each Transaction in a Transaction takes a set of inputs, and produces results. The inputs for a transaction depend on the kind of transaction. Sui supports following transactions:

• tx.splitCoins(coin, amounts) - Creates new coins with the defined amounts, split from the provided coin. Returns the coins so that it can be used in subsequent transactions.
  • Example: tx.splitCoins(tx.gas, [100, 200])
• tx.mergeCoins(destinationCoin, sourceCoins) - Merges the sourceCoins into the destinationCoin.
  • Example: tx.mergeCoins(tx.object(coin1), [tx.object(coin2), tx.object(coin3)])
• tx.transferObjects(objects, address) - Transfers a list of objects to the specified address.
  • Example: tx.transferObjects([tx.object(thing1), tx.object(thing2)], myAddress)
• tx.moveCall({ target, arguments, typeArguments }) - Executes a Move call. Returns whatever the Sui Move call returns.
  • Example: tx.moveCall({ target: '0x2::devnet_nft::mint', arguments: [tx.pure.string(name), tx.pure.string(description), tx.pure.string(image)] })
• tx.makeMoveVec({ type, elements }) - Constructs a vector of objects that can be passed into a moveCall. This is required as there’s no way to define a vector as an input.
  • Example: tx.makeMoveVec({ elements: [tx.object(id1), tx.object(id2)] })
• tx.publish(modules, dependencies) - Publishes a Move package. Returns the upgrade capability object.

Passing inputs to a transaction

Transaction inputs can be provided in a number of different ways, depending on the transaction, and the type of value being provided.

JavaScript values

For specific transaction arguments (amounts in splitCoins, and address in transferObjects) the expected type is known ahead of time, and you can directly pass raw javascript values when calling the transaction method. appropriate Move type automatically.

// the amount to split off the gas coin is provided as a pure javascript number
const [coin] = tx.splitCoins(tx.gas, [100]);
// the address for the transfer is provided as a pure javascript string
tx.transferObjects([coin], '0xSomeSuiAddress');

Pure values

When providing inputs that are not on chain objects, the values must be serialized as

BCS (opens in a new tab), which can be done using tx.pure eg, tx.pure.address(address) or tx.pure(bcs.vector(bcs.U8).serialize(bytes)).

tx.pure can be called as a function that accepts a SerializedBcs object, or as a namespace that contains functions for each of the supported types.

const [coin] = tx.splitCoins(tx.gas, [tx.pure.u64(100)]);
const [coin] = tx.splitCoins(tx.gas, [tx.pure(bcs.U64.serialize(100))]);
tx.transferObjects([coin], tx.pure.address('0xSomeSuiAddress'));
tx.transferObjects([coin], tx.pure(bcs.Address.serialize('0xSomeSuiAddress')));

Object references

To use an on chain object as a transaction input, you must pass a reference to that object. This can be done by calling tx.object with the object id. Transaction arguments that only accept objects (like objects in transferObjects) will automatically treat any provided strings as objects ids. For methods like moveCall that accept both objects and other types, you must explicitly call tx.object to convert the id to an object reference.

// Object IDs can be passed to some methods like (transferObjects) directly
tx.transferObjects(['0xSomeObject'], 'OxSomeAddress');
// tx.object can be used anywhere an object is accepted
tx.transferObjects([tx.object('0xSomeObject')], 'OxSomeAddress');
 
tx.moveCall({
	target: '0x2::nft::mint',
	// object IDs must be wrapped in moveCall arguments
	arguments: [tx.object('0xSomeObject')],
});
 
// tx.object automaically converts the object ID to receiving transaction arguments if the moveCall expects it
tx.moveCall({
	target: '0xSomeAddress::example::receive_object',
	// 0xSomeAddress::example::receive_object expects a receiving argument and has a Move definition that looks like this:
	// public fun receive_object<T: key>(parent_object: &mut ParentObjectType, receiving_object: Receiving<ChildObjectType>) { ... }
	arguments: [tx.object('0xParentObjectID'), tx.object('0xReceivingObjectID')],
});

When building a transaction, Sui expects all objects to be fully resolved, including the object version. The SDK automatically looks up the current version of objects for any provided object reference when building a transaction. If the object reference is used as a receiving argument to a moveCall, the object reference is automatically converted to a receiving transaction argument. This greatly simplifies building transactions, but requires additional RPC calls. You can optimize this process by providing a fully resolved object reference instead:

// for owned or immutable objects
tx.object(Inputs.ObjectRef({ digest, objectId, version }));
 
// for shared objects
tx.object(Inputs.SharedObjectRef({ objectId, initialSharedVersion, mutable }));
 
// for receiving objects
tx.object(Inputs.ReceivingRef({ digest, objectId, version }));

Transaction results

You can also use the result of a transaction as an argument in a subsequent transactions. Each transaction method on the transaction builder returns a reference to the transaction result.

// split a coin object off of the gas object
const [coin] = tx.splitCoins(tx.gas, [100]);
// transfer the resulting coin object
tx.transferObjects([coin], address);

When a transaction returns multiple results, you can access the result at a specific index either using destructuring, or array indexes.

// destructuring (preferred, as it gives you logical local names)
const [nft1, nft2] = tx.moveCall({ target: '0x2::nft::mint_many' });
tx.transferObjects([nft1, nft2], address);
 
// array indexes
const mintMany = tx.moveCall({ target: '0x2::nft::mint_many' });
tx.transferObjects([mintMany[0], mintMany[1]], address);

Get transaction bytes

If you need the transaction bytes, instead of signing or executing the transaction, you can use the build method on the transaction builder itself.

Important: You might need to explicitly call setSender() on the transaction to ensure that the sender field is populated. This is normally done by the signer before signing the transaction, but will not be done automatically if you’re building the transaction bytes yourself.

const tx = new Transaction();
 
// ... add some transactions...
 
await tx.build({ client });

In most cases, building requires your SuiClient to fully resolve input values.

If you have transaction bytes, you can also convert them back into a Transaction class:

const bytes = getTransactionBytesFromSomewhere();
const tx = Transaction.from(bytes);