Scaffold Sei

Create a Next.js dApp with wallet integration and Sei network configuration

@sei-js/create-sei creates a Next.js dApp with TypeScript, wallet integration, and Sei network configuration.

npx @sei-js/create-sei app -n my-sei-app

The generated project includes wagmi, viem, RainbowKit, TypeScript, Tailwind CSS, Mantine UI, and Biome. It pins @sei-js/precompiles 3.x.

Quick start

You do not need to install @sei-js/create-sei globally. -n and --name are the same option.

npx

npx @sei-js/create-sei app -n my-sei-app

bunx

bunx @sei-js/create-sei app -n my-sei-app

The project name must be an unscoped lowercase npm package name, for example my-sei-app. The CLI rejects scoped names, spaces, and most punctuation.

Interactive setup

1. Run the CLI

   To enter the project name interactively, run the command without -n:

   npx @sei-js/create-sei app
   
2. Install and run

   cd my-sei-app
   bun install
   bun run dev
   
3. Start building

   Open http://localhost:3000. If NEXT_PUBLIC_CHAIN is not set, the generated dApp connects to Sei Mainnet. To use Sei Testnet, set NEXT_PUBLIC_CHAIN=testnet in .env.local. The template’s .env.example already sets that value. If you copy it to .env.local, the dApp uses Sei Testnet.

CLI options

Command	Description
app	Create a new Sei dApp
app -n <name>	Specify a project name (--name is the same flag)
app --extension <ext>	Add an optional extension to your project
list-extensions	List available extensions

Default template

The default template is a Next.js EVM dApp. It uses wagmi and viem for typed blockchain interactions. RainbowKit handles wallet connections. It defaults to the generic injected connector, not a MetaMask-only setup.

The template pins Next.js 15, React 19, wagmi 2, viem 2, RainbowKit 2, and TanStack Query 5. It also pins Tailwind CSS 4, Mantine 8, Biome 2, and @sei-js/precompiles 3.x. The exact versions are in the generated package.json.

npx @sei-js/create-sei app -n my-sei-app

The template declares packageManager: bun@1.3.14. Use Bun 1.3.14 or newer for bun install and bun run dev. Its overrides block pins patched transitive dependencies in the npm and Bun format. Yarn reads resolutions, and pnpm reads pnpm.overrides. Both skip those pins and resolve a different, unverified dependency graph.

WalletConnect-based wallets need NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID in .env.local. The injected connector works without it.

The template disables Next.js image optimization because of a Sharp version conflict. As a result, next/image serves unoptimized images.

Extensions

Use an extension to add an example to the base template.

List available extensions

npx @sei-js/create-sei list-extensions

Precompiles extension

Add a Bank precompile example that queries the native SEI supply:

npx @sei-js/create-sei app -n my-sei-precompile-app --extension precompiles

Included configuration

• Next.js App Router project structure
• Wallet connections through wagmi, RainbowKit, and the injected browser-wallet connector
• Sei Mainnet and Sei Testnet configuration through NEXT_PUBLIC_CHAIN
• TypeScript, Biome, Mantine UI, and Tailwind CSS

To run the CLI with npx, install Node.js 20 or newer. The generated project’s .nvmrc pins that version. To install and run the generated project, install Bun 1.3.14 or newer.

Troubleshooting

• If bun install fails, confirm that bun --version reports 1.3.14 or newer.
• If you get a Node.js version conflict when you run npx, use nvm to switch to Node 20 or newer.
• If you get npm permission errors, do not use sudo. Use nvm or fix your npm permissions.
• If the registry times out, run npm config set registry https://registry.npmjs.org/ before you run npx again.