Solana Kit

Solana Kit

@solana/kit is the JavaScript SDK for building Solana applications. Modular, tree-shakable, full TypeScript support.

Core Concepts

Imports

// Convenience (includes all packages)
import { address, createSolanaRpc, lamports } from '@solana/kit';

// Individual packages (smaller bundles)
import { address } from '@solana/addresses';
import { createSolanaRpc } from '@solana/rpc';

Codec Direction

• encode(): values → Uint8Array
• decode(): Uint8Array → values

Branded Types

import { address, lamports, signature } from '@solana/kit';
const myAddress = address('So11111111111111111111111111111111111111112');
const myLamports = lamports(1_000_000_000n);

Quick Patterns

RPC Client

import { createSolanaRpc, createSolanaRpcSubscriptions, devnet } from '@solana/kit';

const rpc = createSolanaRpc(devnet('https://api.devnet.solana.com'));
const rpcSubs = createSolanaRpcSubscriptions(devnet('wss://api.devnet.solana.com'));

Build & Send Transaction

import {
  pipe, createTransactionMessage, setTransactionMessageFeePayerSigner,
  setTransactionMessageLifetimeUsingBlockhash, appendTransactionMessageInstruction,
  signAndSendTransactionMessageWithSigners,
} from '@solana/kit';

const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();

const message = pipe(
  createTransactionMessage({ version: 0 }),
  m => setTransactionMessageFeePayerSigner(signer, m),
  m => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, m),
  m => appendTransactionMessageInstruction(myInstruction, m),
);

const signature = await signAndSendTransactionMessageWithSigners(message);

Compute Budget (Required for production)

Always set compute units and priority fee:

import {
  getSetComputeUnitPriceInstruction,
  estimateComputeUnitLimitFactory,
  estimateAndUpdateProvisoryComputeUnitLimitFactory,
} from '@solana-program/compute-budget';

// Setup estimator
const estimateAndUpdateCU = estimateAndUpdateProvisoryComputeUnitLimitFactory(
  estimateComputeUnitLimitFactory({ rpc })
);

// Build message with priority fee
let message = pipe(
  createTransactionMessage({ version: 0 }),
  m => setTransactionMessageFeePayerSigner(signer, m),
  m => setTransactionMessageLifetimeUsingBlockhash(blockhash, m),
  m => appendTransactionMessageInstruction(instruction, m),
  m => prependTransactionMessageInstruction(getSetComputeUnitPriceInstruction({ microLamports: 1000n }), m),
);

// Estimate and set CU limit via simulation
message = await estimateAndUpdateCU(message);

// ⚠️ IMPORTANT: Refresh blockhash after estimation (simulation takes time)
const { value: freshBlockhash } = await rpc.getLatestBlockhash().send();
message = setTransactionMessageLifetimeUsingBlockhash(freshBlockhash, message);

Fetch Account

import { fetchEncodedAccount, assertAccountExists, decodeAccount } from '@solana/kit';

const account = await fetchEncodedAccount(rpc, myAddress);
assertAccountExists(account);
const decoded = decodeAccount(account, myDecoder);

Codec Example

import { getStructCodec, getU32Codec, getU64Codec, addCodecSizePrefix, getUtf8Codec } from '@solana/kit';

type MyData = { name: string; amount: bigint };
const codec = getStructCodec([
  ['name', addCodecSizePrefix(getUtf8Codec(), getU32Codec())],
  ['amount', getU64Codec()],
]);

const bytes = codec.encode({ name: 'test', amount: 100n });
const data = codec.decode(bytes);

Package Overview

Best Practices

1. Use pipe() for transaction building
2. Use branded types — address(), lamports(), signature()
3. Always set compute budget — estimate CUs, set priority fee
4. Handle account existence — assertAccountExists() before decode
5. Use factories — sendAndConfirmTransactionFactory(), airdropFactory()

Reference Files

For detailed patterns:

• references/accounts.md — Fetching, parsing, decoding accounts
• references/codecs.md — Complete codec patterns
• references/rpc.md — RPC methods and subscriptions
• references/react.md — React hooks and wallet integration
• references/transactions.md — Transaction building, signing, compute budget

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