> ## Documentation Index > Fetch the complete documentation index at: https://docs.dynamic.xyz/docs/llms.txt > Use this file to discover all available pages before exploring further. # JavaScript SDK Overview > A headless, framework-agnostic SDK for authentication, wallets, and signing. You build the UI — Dynamic handles everything else. The JavaScript SDK (`@dynamic-labs-sdk/client`) works in **any environment that runs JavaScript** — React, React Native, Vue, Svelte, vanilla JS, or another framework. It 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. > [!TIP] > > This SDK is headless: there is no built-in modal or login form, and you control every pixel of the UI. See the [Building UI guides](https://docs.dynamic.xyz/docs/javascript/building-ui/overview.md) for real-world flows built end to end. For React web apps, [React UI components](https://docs.dynamic.xyz/docs/javascript/building-ui/react-ui/overview.md) also provide prebuilt widgets for wallet connection and Flow payments. ## Choose your quickstart Pick the path that matches how you build: > [card] [React](https://docs.dynamic.xyz/docs/javascript/reference/react-quickstart.md) > > React apps with `@dynamic-labs-sdk/react-hooks`. > [card] [React Native](https://docs.dynamic.xyz/docs/javascript/reference/react-native-quickstart.md) > > Expo or bare React Native with the same client and hooks. > [card] [Vanilla JavaScript](https://docs.dynamic.xyz/docs/javascript/reference/quickstart.md) > > Framework-free or any other JS environment. ## How it works **1. Create a client** Call `createDynamicClient()` with your environment ID from the [Dynamic Console](https://console.dynamic.xyz). 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. ## 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 > [!TIP] > > See [Authentication screens](https://docs.dynamic.xyz/docs/javascript/authentication-methods/headless-authentication.md) for the full list with implementation guides. ## 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 * **Earn** — let users deposit into curated yield vaults, track positions, and claim rewards (EVM only) ## 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 │ │ │ └─────────────────────────────────────┘ │ └─────────────────────────────────────────────┘ ``` ## Use with React and React Native For React (web), `@dynamic-labs-sdk/react-hooks` wraps client functions as hooks so components re-render when state changes. See the [React Hooks guide](https://docs.dynamic.xyz/docs/javascript/reference/react-hooks-guide.md). For React Native (Expo or bare), you add polyfills, native modules, and deep-link metadata — then auth, wallets, and signing match the web guides. See [React Native Setup](https://docs.dynamic.xyz/docs/javascript/react-native/setup.md) for Expo vs bare details. ## Common mistakes | Mistake | Fix | | :- | :- | | Using `@dynamic-labs/sdk-react-core` without React | Use `@dynamic-labs-sdk/client` instead | | Installing `@dynamic-labs/legacy-client` for React Native | That is the **legacy** RN SDK — use `@dynamic-labs-sdk/client` ([React Native Quickstart](https://docs.dynamic.xyz/docs/javascript/reference/react-native-quickstart.md)) | | Adding `@dynamic-labs/legacy-web-extension` | Not needed — that package is for React Native on web | | Loading SDK via `