#table-of-contents-content a[href="#here%E2%80%99s-how-that-works%3A"] {
  /* Hides the 'Here's how that works:' link in the table of contents.
     Ensure the href matches the exact text content to maintain this behavior.
     Link: /home#here%E2%80%99s-how-that-works%3A */
  display: none;
}

#table-of-contents-content a[href^="#feature-spotlight"] {
  /* Hides the 'Feature spotlight: Send crypto via a URL' link in the table of contents.
     Ensure the href starts with '#feature-spotlight' to maintain this behavior.
     Link: /home#feature-spotlight%3A-send-crypto-via-a-url */
  display: none;
}


Function: assertNonNull()

Type Parameters

input

Parameters

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AssertNonNull

Turnkey

Welcome to Turnkey! To make the most out of Turnkey's wallet infrastructure, we've compiled a list of helpful resources for you below.

Welcome

Getting started with Turnkey

Introduction

Embedded Wallets

Turnkey has built a new model for private key management that utilizes secure enclaves. All transactions are signed within an enclave and private keys are never exposed to Turnkey, your software, or your team. Turnkey’s role is similar to that of a safety deposit box operator — Turnkey secures and provides access to the safety deposit boxes, but our system requires cryptographic proof of ownership to take any action with the keys held within.

Integrating Embedded Wallets

Email auth is a powerful feature to couple with [sub-organizations](/concepts/sub-organizations) for your users. This approach empowers your users to authenticate their Turnkey in a simple way (via email!), while minimizing your involvement: we engineered this feature to ensure your organization is unable to take over sub-organizations even if it wanted to.

Email Authentication

Email recovery shines if you are leveraging [sub-organizations](/concepts/sub-organizations) to create embedded wallets for your users. This allows your users to recover their Turnkey account if something goes wrong with their passkeys, and keeps you out of the loop: we engineered this feature to ensure your organization is unable to take over sub-organizations even if it wanted to.

Email Recovery

Turnkey offers flexible infrastructure to create and manage keys. These keys can be used as a signer inside of an [Account Abstraction wallet](https://www.erc4337.io/), and we've partnered with [Alchemy](https://www.alchemy.com/) and [ZeroDev](https://zerodev.app/) to integrate in a few lines of code.

Account Abstraction Wallets

Turnkey offers a suite of react components to create embedded wallets without having to setup a backend by using Next.js [server actions](https://nextjs.org/docs/app/building-your-application/data-fetching/server-actions-and-mutations) and associated directives. Each component uses the **authIframeClient** from [@turnkey/sdk-react](https://www.npmjs.com/package/@turnkey/sdk-react).

Embedded Wallet Kit (EWK)

Signing Automation

Learn how to set up and use co-signing (multi-sig) wallets with Turnkey.

Co-signing Transactions

Sdks

Turnkey provides a variety of client and server SDKs which simplify interacting with Turnkey's API. The SDKs offer methods, utilities, and helper functions to quickly implement features and perform common workflows.

SDK Reference

JavaScript Browser

The [`@turnkey/sdk-server`](https://www.npmjs.com/package/@turnkey/sdk-server) package exposes functionality that lets developers build server-side functionality for applications that interact with the Turnkey API.

JavaScript Server

React

This documentation contains guides for using Turnkey's React Native compatible [JavaScript packages](https://github.com/tkhq/sdk/tree/main/packages).

React Native

Turnkey offers native tooling for interacting with the API using Golang. See [https://github.com/tkhq/go-sdk](https://github.com/tkhq/go-sdk) for more details.

Golang

Turnkey offers native tooling for interacting with the API using Rust. See [https://github.com/tkhq/rust-sdk](https://github.com/tkhq/rust-sdk) for more details.

Rust

Ruby

This quickstart will guide you through Turnkey’s onboarding, adding an API key, creating a wallet, and signing your first Ethereum transaction.

Command Line

Using the CLI

This documentation contains guides for using the Flutter SDK.

Flutter

This guide aims to cover the process for migrating from lower-level Turnkey SDK (i.e. `@turnkey/{ http, api-key-stamper, webauthn-stamper, iframe-stamper }`) libraries, to our more recent abstractions: `@turnkey/{ sdk-browser, sdk-server, sdk-react }`

Migration Path

Review our [API Introduction](/developer-reference/api-overview/intro) to get started.

SDK Reference

​Function: assertNonNull()

​Type Parameters

​T

​Parameters

​input

​Returns

Function: assertNonNull()

Type Parameters

T

Parameters

input

Returns