Getting Started

A Typescript SDK to interact with Crossmint Wallets. This SDK enables developers to create and manage smart contract wallets that support both traditional keypair-based signing and passkey authentication across Solana and EVM chains.

• Multi-chain: supports Solana and EVM chains
• Multiple signer types: passkeys, ECDSA keypairs, delegated signers
• Smart and MPC wallets
• User (client-side) wallets and agent (server-side) wallets
• Familiar API: follows viem and web3.js conventions

Installation

npm install @crossmint/wallets-sdk
# or
pnpm add @crossmint/wallets-sdk

Quick Start

import { CrossmintWallets, createCrossmint } from "@crossmint/wallets-sdk";

const crossmint = createCrossmint({
    apiKey: "<YOUR_API_KEY>",
    jwt: "<USER_TOKEN>", // Not needed for server wallets
});
const crossmintWallets = CrossmintWallets.from(crossmint);
const wallet = await crossmintWallets.getOrCreateWallet("evm-smart-wallet", {
    chain: "base-sepolia",
    adminSigner: {
        type: "evm-passkey",
    },
});

const address = wallet.address;

Solana Examples

Wallet Creation

Smart Wallets

import { Keypair } from "@solana/web3.js";

const keypair = Keypair.generate();
const wallet = await crossmintWallets.getOrCreateWallet("solana-smart-wallet", {
    adminSigner: {
        type: "solana-keypair",
        signer: keypair,
        address: keypair.publicKey.toBase58(),
    },
});

MPC Wallets

const wallet = await crossmintWallets.getOrCreateWallet("solana-mpc-wallet", {
    linkedUser: "<USER_UD>",
});

Sending Transactions

import {
    Connection,
    PublicKey,
    TransactionInstruction,
    TransactionMessage,
    VersionedTransaction,
} from "@solana/web3.js";

const connection = new Connection("https://api.devnet.solana.com");
const memoInstruction = new TransactionInstruction({
    keys: [
        {
            pubkey: new PublicKey(wallet.getAddress()),
            isSigner: true,
            isWritable: true,
        },
    ],
    data: Buffer.from("Hello from Crossmint SDK", "utf-8"),
    programId: new PublicKey("MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr"),
});

const blockhash = (await connection.getLatestBlockhash()).blockhash;
const newMessage = new TransactionMessage({
    payerKey: new PublicKey(wallet.getAddress()),
    recentBlockhash: blockhash,
    instructions: [memoInstruction],
});

const transaction = new VersionedTransaction(newMessage.compileToV0Message());

const txHash = await wallet.sendTransaction({
    transaction,
});

Delegated Signers

const newSigner = Keypair.generate();
await wallet.addDelegatedSigner(keypair.publicKey.toBase58());
const txHash = await wallet.sendTransaction({
    transaction,
    delegatedSigner: {
        type: "solana-keypair",
        address: keypair.publicKey.toBase58(),
        signer: newSigner,
    },
});

EVM Examples

Wallet Creation

Passkey Smart Wallets

const wallet = await crossmintWallets.getOrCreateWallet("evm-smart-wallet", {
    chain: "base-sepolia",
    adminSigner: {
        type: "evm-passkey",
        name: "My Wallet",
    },
});

Keypair Smart Wallets

import { generatePrivateKey, privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(generatePrivateKey());
const wallet = await crossmintWallets.getOrCreateWallet("evm-smart-wallet", {
    chain: "base-sepolia",
    adminSigner: {
        type: "evm-keypair",
        address: account.address,
        signer: {
            type: "viem_v2",
            account,
        },
    },
});

Sending Transactions

const transaction = await wallet.sendTransaction({
    to: "0x0000000000000000000000000000000000000042",
    data: "0xdeadbeef",
    value: BigInt(0),
});

Signing Messages

const signature = await wallet.signMessage({
    message: "Hello from Crossmint SDK",
});