solana_kit_transactions 0.2.0

Transaction compilation and signing for the Solana Kit Dart SDK.

solana_kit_transactions

Compile, sign, encode, and decode Solana transactions.

This is the Dart port of @solana/transactions from the Solana TypeScript SDK.

Installation

dependencies:
  solana_kit_transactions:

Since this package is part of the solana_kit workspace, you can also use the umbrella package:

dependencies:
  solana_kit:

Documentation

• Package page: https://pub.dev/packages/solana_kit_transactions
• API reference: https://pub.dev/documentation/solana_kit_transactions/latest/

Usage

Compiling a transaction

A Transaction is compiled from a TransactionMessage that has a fee payer and a lifetime constraint. The compiled transaction includes the wire-format message bytes and a signatures map with null entries for each required signer.

import 'dart:typed_data';

import 'package:solana_kit_addresses/solana_kit_addresses.dart';
import 'package:solana_kit_instructions/solana_kit_instructions.dart';
import 'package:solana_kit_transaction_messages/solana_kit_transaction_messages.dart';
import 'package:solana_kit_transactions/solana_kit_transactions.dart';

final myAddress = Address('mpngsFd4tmbUfzDYJayjKZwZcaR7aWb2793J6grLsGu');

// Build a transaction message (see solana_kit_transaction_messages).
final txMessage = TransactionMessage(
  version: TransactionVersion.v0,
  feePayer: myAddress,
  instructions: [
    Instruction(
      programAddress: Address('11111111111111111111111111111111'),
      accounts: [
        AccountMeta(address: myAddress, role: AccountRole.writableSigner),
        AccountMeta(
          address: Address('GDhQoTpNbYUaCAjFKBMCPCdrCaKaLiSqhx5M7r4SrEFy'),
          role: AccountRole.writable,
        ),
      ],
      data: Uint8List.fromList([2, 0, 0, 0, 0, 202, 154, 59, 0, 0, 0, 0]),
    ),
  ],
  lifetimeConstraint: BlockhashLifetimeConstraint(
    blockhash: 'EkSnNWid2cvwEVnVx9aBqawnmiCNiDgp3gUdkDPTKN1N',
    lastValidBlockHeight: BigInt.from(300000),
  ),
);

// Compile the message into a transaction. Signatures are initially null.
final transaction = compileTransaction(txMessage);
print(transaction.signatures); // {Address('mpngs...'): null}

Signing transactions

Sign a transaction with one or more KeyPair objects. Use signTransaction to sign and assert all required signatures are present, or partiallySignTransaction when you only have a subset of signers.

import 'package:solana_kit_keys/solana_kit_keys.dart';
import 'package:solana_kit_transactions/solana_kit_transactions.dart';

Future<void> main() async {
  // Generate an Ed25519 key pair for the fee payer.
  final keyPair = await generateKeyPair();

  // Sign the transaction (throws if not all signers are provided).
  final signedTx = await signTransaction([keyPair], transaction);

  // Or partially sign (does not require all signers).
  final partiallySigned = await partiallySignTransaction(
    [keyPair],
    transaction,
  );

  // Check if a transaction is fully signed.
  print(isFullySignedTransaction(signedTx)); // true
}

Getting the transaction signature

The transaction signature (also called the transaction ID) is the fee payer's signature:

final signature = getSignatureFromTransaction(signedTx);
print(signature); // The base58-encoded transaction signature.

Checking the transaction size

Solana transactions must fit within 1232 bytes (the MTU minus network header overhead). This package provides helpers to check and assert size constraints:

import 'package:solana_kit_transactions/solana_kit_transactions.dart';

// Get the size in bytes of a compiled transaction.
final size = getTransactionSize(transaction);
print(size);

// Check against the 1232-byte limit.
print(isTransactionWithinSizeLimit(transaction)); // true or false

// Throws SolanaError if the transaction exceeds the size limit.
assertIsTransactionWithinSizeLimit(transaction);

// You can also check the size directly from a TransactionMessage,
// which compiles it internally.
final messageSize = getTransactionMessageSize(txMessage);
print(isTransactionMessageWithinSizeLimit(txMessage));

Encoding and decoding transactions

Use codecs to convert transactions to and from their wire format:

import 'package:solana_kit_transactions/solana_kit_transactions.dart';

void main() {
  // Encode a transaction to bytes (wire format).
  final encoder = getTransactionEncoder();
  final wireBytes = encoder.encode(signedTx);

  // Decode a transaction from wire bytes.
  final decoder = getTransactionDecoder();
  final (decodedTx, _) = decoder.read(wireBytes, 0);

  // Or use the combined codec.
  final codec = getTransactionCodec();
  final roundTripped = codec.decode(codec.encode(signedTx));
}

Getting a base64 wire transaction

For sending transactions via RPC, you typically need the base64-encoded wire transaction:

import 'package:solana_kit_transactions/solana_kit_transactions.dart';

void main() {
  final base64Wire = getBase64EncodedWireTransaction(signedTx);
  print(base64Wire); // Base64-encoded string ready for sendTransaction RPC.
}

Sendable transaction checks

A transaction is sendable if it is fully signed and within the size limit:

import 'package:solana_kit_transactions/solana_kit_transactions.dart';

void main() {
  print(isSendableTransaction(signedTx)); // true

  // Throws if not sendable.
  assertIsSendableTransaction(signedTx);
}

Transaction lifetime constraints

Transactions carry lifetime metadata. This package provides types and checkers for both blockhash and durable nonce lifetimes:

import 'package:solana_kit_transactions/solana_kit_transactions.dart';

void main() {
  // Check blockhash lifetime.
  print(isTransactionWithBlockhashLifetime(transaction)); // true

  // Check durable nonce lifetime.
  print(isTransactionWithDurableNonceLifetime(transaction)); // false
}

API Reference

Classes

• Transaction -- A compiled transaction with messageBytes and signatures map.
• TransactionWithLifetime -- Extends Transaction with a lifetimeConstraint (either TransactionBlockhashLifetime or TransactionDurableNonceLifetime).
• TransactionBlockhashLifetime -- Blockhash-based lifetime with blockhash and lastValidBlockHeight.
• TransactionDurableNonceLifetime -- Durable nonce lifetime with nonce and nonceAccountAddress.

Functions

Function	Description
compileTransaction	Compiles a TransactionMessage into a TransactionWithLifetime.
signTransaction	Signs a transaction and asserts it is fully signed.
partiallySignTransaction	Signs a transaction with a subset of required signers.
isFullySignedTransaction	Returns true if all signers have provided signatures.
assertIsFullySignedTransaction	Throws if any signer signature is missing.
getSignatureFromTransaction	Returns the fee payer's signature (the transaction ID).
getTransactionSize	Returns the encoded size in bytes.
isTransactionWithinSizeLimit	Returns true if the transaction fits within 1232 bytes.
assertIsTransactionWithinSizeLimit	Throws if the transaction exceeds the size limit.
getTransactionMessageSize	Returns the compiled transaction size from a TransactionMessage.
isTransactionMessageWithinSizeLimit	Returns true if the compiled message fits within the limit.
assertIsTransactionMessageWithinSizeLimit	Throws if the compiled message exceeds the limit.
isSendableTransaction	Returns true if fully signed and within size limit.
assertIsSendableTransaction	Throws if the transaction is not sendable.
getTransactionEncoder	Returns a wire-format encoder for Transaction.
getTransactionDecoder	Returns a wire-format decoder for Transaction.
getTransactionCodec	Returns a combined encoder/decoder codec.
getBase64EncodedWireTransaction	Returns a base64-encoded wire transaction string.
isTransactionWithBlockhashLifetime	Returns true if the transaction has a blockhash lifetime.
assertIsTransactionWithBlockhashLifetime	Throws if the transaction does not have a blockhash lifetime.
isTransactionWithDurableNonceLifetime	Returns true if the transaction has a durable nonce lifetime.
assertIsTransactionWithDurableNonceLifetime	Throws if the transaction does not have a durable nonce lifetime.

Constants

• transactionPacketSize -- Maximum network packet size: 1280 bytes.
• transactionPacketHeader -- Network header overhead: 48 bytes (IPv6 + fragment header).
• transactionSizeLimit -- Maximum transaction content size: 1232 bytes.

Example

Use example/main.dart as a runnable starting point for solana_kit_transactions.

• Import path: package:solana_kit_transactions/solana_kit_transactions.dart
• This section is centrally maintained with mdt to keep package guidance aligned.
• After updating shared docs templates, run docs:update from the repo root.

Maintenance

• Validate docs in CI and locally with docs:check.
• Keep examples focused on one workflow and reference package README sections for deeper API details.