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The JavaScript SDK (@dynamic-labs-sdk/client) gives you full control over authentication, wallet connections, and transaction signing without any built-in UI. You create a Dynamic client, add extensions for the chains you support, and call functions directly — rendering every screen, button, and input yourself.
This SDK is headless. There is no built-in modal, wallet picker, or login form. You are responsible for building all user-facing UI.

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How it works

1

Create a client

Call createDynamicClient() with your environment ID from the Dynamic dashboard. This is the single entry point for the SDK.
2

Add extensions

Register chain extensions (e.g. addEvmExtension(), addSolanaExtension()) to enable wallet discovery and signing for each chain you support.
3

Initialize

The client initializes automatically by default. Wait for initialization to complete before calling other SDK functions.
4

Build your UI

Use SDK functions to authenticate users, connect wallets, and sign transactions. You decide what the UI looks like — the SDK provides the logic.

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What you need to build

Because the SDK is headless, your app handles these screens:
  • Login — collect an email/phone, trigger OTP or social auth, and verify the response
  • Wallet picker — list available wallet providers and let the user choose one
  • MFA prompts — prompt for TOTP codes or passkey verification when MFA is enabled
  • Step-up authentication — re-verify identity before sensitive actions
  • Device registration — verify the user’s email when they sign in from an unrecognized device
See Authentication screens for the full list with implementation guides.

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What the SDK handles

You call functions; the SDK manages the rest:
  • Authentication — email OTP, SMS, social login, passkeys, external JWTs, and MFA
  • Wallet management — embedded wallets (MPC-backed, user-owned) and external wallets (MetaMask, Phantom, etc.)
  • Transaction signing — chain-specific signing, typed data, and message signing
  • Session management — JWTs, token refresh, and logout
  • Events — subscribe to auth, wallet, and session state changes with onEvent()
  • Multi-chain — EVM, Solana, Bitcoin, Aptos, Sui, TON, Tron, and Starknet via extensions
  • Gasless transactions — sponsor gas so users don’t pay, on both EVM (via ZeroDev) and Solana
  • Fireblocks Flow — accept crypto from any wallet or exchange and settle in a token and chain you choose

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Architecture

The SDK creates and manages a hidden iframe internally for WaaS/MPC key operations. You do not need to configure or install a separate iframe host package. 
┌─────────────────────────────────────────────┐
│  Your web app (any framework or none)       │
│                                             │
│  @dynamic-labs-sdk/client                   │
│  @dynamic-labs-sdk/evm (or /solana, etc.)   │
│                                             │
│  ┌─────────────────────────────────────┐    │
│  │  Hidden iframe (MPC key operations) │    │
│  │  Managed internally by the SDK      │    │
│  └─────────────────────────────────────┘    │
└─────────────────────────────────────────────┘

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Use with React

The JavaScript SDK works in any JavaScript environment, including React. The @dynamic-labs-sdk/react-hooks package wraps client functions as React hooks so your components re-render automatically when state changes. See the React Quickstart (JS SDK) to get started, or the React Hooks guide for details on how hooks map to client functions.

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Common mistakes

MistakeFix
Using @dynamic-labs/sdk-react-core without ReactUse @dynamic-labs-sdk/client instead
Adding @dynamic-labs/web-extensionNot needed — that package is for React Native on web
Loading SDK via <script> tag without a bundlerUse Vite, webpack, or another bundler
Expecting a built-in modal or wallet pickerThe JS SDK is headless — build your own UI
Calling createDynamicClient inside a render loopCreate the client once at app startup

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What’s next

Quickstart

Install the SDK, create a client, and authenticate a user.

Wallets

Build a wallet picker, connect wallets, and manage accounts.

Fireblocks Flow

Accept crypto payments and settle in any token or chain.

User & Session Management

Check sign-in state, read user data, and manage sessions.