@solana/kit vs @solana/web3.js
@solana/kit is the next-generation Solana JavaScript SDK, replacing @solana/web3.js 1.x. It is a ground-up rewrite with a modular architecture, tree-shakeable exports, and a functional API instead of class-based patterns.
Comparison
| Feature | @solana/web3.js 1.x | @solana/kit |
|---|---|---|
| Architecture | Monolithic, class-based | Modular, functional |
| Bundle size | ~100KB+ (full import) | Tree-shakeable (import only what you use) |
| Key handling | Keypair class | CryptoKeyPair (Web Crypto API) |
| Transaction building | Transaction / VersionedTransaction classes | Functional builders with pipe pattern |
| RPC client | Connection class | createSolanaRpc() with typed methods |
| TypeScript | Partial types | Full type safety, branded types |
| Runtime | Node.js focused | Browser and Node.js (Web Crypto) |
| Status | Maintenance mode | Active development |
Key differences
Key generation
// web3.js 1.x
import { Keypair } from "@solana/web3.js";
const keypair = Keypair.generate();
const pubkey = keypair.publicKey.toBase58();
// @solana/kit
import { generateKeyPairSigner } from "@solana/kit";
const signer = await generateKeyPairSigner();
const address = signer.address;RPC calls
// web3.js 1.x
import { Connection } from "@solana/web3.js";
const connection = new Connection("https://api.mainnet-beta.solana.com");
const balance = await connection.getBalance(pubkey);
// @solana/kit
import { createSolanaRpc } from "@solana/kit";
const rpc = createSolanaRpc("https://api.mainnet-beta.solana.com");
const balance = await rpc.getBalance(address).send();Transaction building
// web3.js 1.x
const tx = new Transaction().add(
SystemProgram.transfer({ fromPubkey, toPubkey, lamports })
);
tx.sign(keypair);
// @solana/kit
import { pipe } from "@solana/kit";
const tx = pipe(
createTransaction({ version: 0 }),
(tx) => appendTransactionMessageInstruction(tx, transferIx),
);
const signed = await signTransaction([signer], tx);When to use which
| Scenario | Recommendation |
|---|---|
| New project | @solana/kit |
| Existing project (web3.js 1.x) | Continue with web3.js, migrate gradually |
| Library authors | @solana/kit (smaller consumer bundles) |
| Quick prototyping | Either (web3.js has more examples/docs) |
| Browser-first application | @solana/kit (Web Crypto, tree-shaking) |
FAQ
Is @solana/web3.js deprecated?
The 1.x version is in maintenance mode — it receives security fixes but no new features. New projects should use @solana/kit. Existing projects can migrate at their own pace.
Can I use both in the same project?
Yes, during migration. Both can coexist. Convert address types between libraries using address() and new PublicKey().
Is @solana/kit stable?
Yes. The 2.x release (published as @solana/kit) is stable and used in production. The API has stabilized, though some utility packages continue to receive updates.
Updated: