XMTP-JS

XMTP client SDK for JavaScript applications

xmtp-js provides a TypeScript implementation of an XMTP client for use with JavaScript and React applications.

Build with xmtp-js to provide messaging between blockchain wallet addresses, delivering on use cases such as wallet-to-wallet messaging and dapp-to-wallet notifications.

xmtp-js was included in a security assessment prepared by Certik.

To learn more about XMTP and get answers to frequently asked questions, see the XMTP documentation.

Playground and example apps built with xmtp-js

• Use the XMTP React playground app as a tool to start building an app with XMTP. This basic messaging app has an intentionally unopinionated UI to help make it easier for you to build with.

• Use the XMTP Inbox Web example app as a reference implementation to understand how to implement features following developer and user experience best practices.

Reference docs

Access the xmtp-js client SDK reference documentation.

Install

NPM

npm install @xmtp/xmtp-js
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PNPM

pnpm install @xmtp/xmtp-js
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Yarn

yarn add @xmtp/xmtp-js
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Requirements

Buffer polyfill

A Buffer polyfill is required for browser environments.

See this solution for implementation details.

Troubleshoot

WebAssembly issues

This SDK uses WebAssembly, which may require additional configuration in your environment.

Vite

vite.config.js

import { defineConfig } from 'vite'

export default defineConfig({
  optimizeDeps: {
    exclude: ['@xmtp/user-preferences-bindings-wasm'],
  },
})
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Next.js

Configuration is dependent on your version of Next.js.

next.config.mjs

Next.js < 15

const nextConfig = {
  experimental: {
    serverComponentsExternalPackages: ['@xmtp/user-preferences-bindings-wasm'],
  },
}

export default nextConfig
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Next.js >= 15

const nextConfig = {
  serverExternalPackages: ['@xmtp/user-preferences-bindings-wasm'],
}

export default nextConfig
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BigInt polyfill

This SDK uses BigInt in a way that's incompatible with polyfills. To ensure that a polyfill isn't added to your application bundle, update your browserslist configuration to exclude browsers that don't support BigInt.

For the list of browsers that don't support BigInt, see this compatibility list.

Usage

Check out our official documentation to get started developing with XMTP and JavaScript.

Use local storage

Important
If you are building a production-grade app, be sure to use an architecture that includes a local cache backed by an XMTP SDK.

To learn more, see Use local-first architecture.

Interacting with Snaps

If the user has a compatible version of MetaMask installed in their browser, and the useSnaps ClientCreateOption is set to true, the SDK will attempt to install and connect to the "Sign in with XMTP" Snap as part of client creation. If successful, all cryptographic operations will happen inside the secure context of the Snap instead of the main browser thread. This offers greater security and a smoother sign-in experience.

In cases where the Snap is being used, Client.getKeys() will fail because the client application has no access to the private key material when used with Snaps.

Currently, useSnaps uses a default value of false. However, in future versions of xmtp-js, it will be updated to use a default value of true.

Breaking revisions

Because xmtp-js is in active development, you should expect breaking revisions that might require you to adopt the latest SDK release to enable your app to continue working as expected.

XMTP communicates about breaking revisions in the XMTP Discord community, providing as much advance notice as possible. Additionally, breaking revisions in an xmtp-js release are described on the Releases page.

Deprecation

Older versions of the SDK will eventually be deprecated, which means:

1. The network will not support and eventually actively reject connections from clients using deprecated versions.
2. Bugs will not be fixed in deprecated versions.

The following table provides the deprecation schedule.

Announced	Effective	Minimum Version	Rationale
2022-08-18	2022-11-08	v6.0.0	XMTP network will stop supporting the Waku/libp2p-based client interface in favor of the new gRPC-based interface

Issues and PRs are welcome in accordance with our contribution guidelines.

XMTP production and dev network environments

XMTP provides both production and dev network environments to support the development phases of your project.

The production and dev networks are completely separate and not interchangeable. For example, for a given blockchain account address, its XMTP identity on dev network is completely distinct from its XMTP identity on the production network, as are the messages associated with these identities. In addition, XMTP identities and messages created on the dev network can't be accessed from or moved to the production network, and vice versa.

Important
When you create a client, it connects to the XMTP dev environment by default. To learn how to use the env parameter to set your client's network environment, see Configure the client.

The env parameter accepts one of three valid values: dev, production, or local. Here are some best practices for when to use each environment:

• dev: Use to have a client communicate with the dev network. As a best practice, set env to dev while developing and testing your app. Follow this best practice to isolate test messages to dev inboxes.

• production: Use to have a client communicate with the production network. As a best practice, set env to production when your app is serving real users. Follow this best practice to isolate messages between real-world users to production inboxes.

• local: Use to have a client communicate with an XMTP node you are running locally. For example, an XMTP node developer can set env to local to generate client traffic to test a node running locally.

The production network is configured to store messages indefinitely. XMTP may occasionally delete messages and keys from the dev network, and will provide advance notice in the XMTP Discord community.