bun init - Bun

2 min read Original article ↗

Scaffold a new Bun project with bun init.

Press enter to accept the default answer for each prompt, or pass the -y flag to auto-accept the defaults.

bun init infers settings with sane defaults and is non-destructive when run multiple times.

It creates:

  • a package.json file with a name that defaults to the current directory name
  • a tsconfig.json or jsconfig.json file, depending on whether the entry point is a TypeScript file
  • an entry point, which defaults to index.ts unless any of index.{tsx, jsx, js, mts, mjs} exist or the package.json specifies a module or main field
  • a README.md file

AI Agent rules (disable with $BUN_AGENT_RULE_DISABLED=1):

  • a CLAUDE.md file when Claude CLI is detected (disable with CLAUDE_CODE_AGENT_RULE_DISABLED env var)
  • a .cursor/rules/*.mdc file when Cursor is detected, which tells Cursor AI to use Bun instead of Node.js and npm

Pass -y or --yes to accept the defaults without prompting. At the end, it runs bun install to install @types/bun.

CLI Usage

Initialization Options

Accept all default prompts without asking questions. Alias: -y

Only initialize type definitions (skip app scaffolding). Alias: -m

Project Templates

Scaffold a React project. When used without a value, creates a baseline React app.
Accepts values for presets:

  • tailwind – React app preconfigured with Tailwind CSS
  • shadcn – React app with @shadcn/ui and Tailwind CSS

Examples:

bun init —react bun init —react=tailwind bun init —react=shadcn

Output & Files

Initializes project files and configuration for the chosen options. Exact files vary by template.

Help

Print this help menu. Alias: -h

Examples

  • Accept all defaults
  • React
  • React + Tailwind CSS
  • React + @shadcn/ui