# DeerFlow Frontend

Like the original DeerFlow 1.0, we would love to give the community a minimalistic and easy-to-use web interface with a more modern and flexible architecture.

Switching accounts reloads projects, custom agents, models, and other cached workspace data for the new account. Logging out immediately hides the previous account's data; refreshing the same account preserves its cache.

## Tech Stack

- **Framework**: [Next.js 16](https://nextjs.org/) with [App Router](https://nextjs.org/docs/app)
- **UI**: [React 19](https://react.dev/), [Tailwind CSS 4](https://tailwindcss.com/), [Shadcn UI](https://ui.shadcn.com/), [MagicUI](https://magicui.design/) and [React Bits](https://reactbits.dev/)
- **AI Integration**: [LangGraph SDK](https://www.npmjs.com/package/@langchain/langgraph-sdk) and [Vercel AI Elements](https://vercel.com/ai-sdk/ai-elements)

## Quick Start

### Prerequisites

- Node.js 22+
- pnpm 10.26.2+

### Installation

```bash
# Install dependencies
pnpm install

# Copy environment variables
cp .env.example .env
# Edit .env with your configuration
```

### Development

```bash
# Start development server
pnpm dev

# The app will be available at http://localhost:3000
```

### Build & Test

```bash
# Type check
pnpm typecheck

# Check formatting
pnpm format

# Apply formatting
pnpm format:write

# Lint
pnpm lint

# Run unit tests
pnpm test

# One-time setup: install Playwright Chromium browser
pnpm exec playwright install chromium

# Run E2E tests (builds and starts production server automatically)
pnpm test:e2e

# Build for production
pnpm build

# Start production server
pnpm start
```

Production builds recreate `public/_pagefind/` from the current documentation,
with separate English and Chinese indexes. The index step replaces its generated
output directory to prevent old assets accumulating. Mobile docs search results scroll inside
the menu and close it after selection, including the section already open.

## Site Map

```
├── /                    # Landing page
├── /chats               # Chat list
├── /chats/new           # New chat page
└── /chats/[thread_id]   # A specific chat page
```

## Configuration

### Environment Variables

Key environment variables (see `.env.example` for full list):

```bash
# Backend API URL (optional, uses local Next.js/nginx proxy by default)
NEXT_PUBLIC_BACKEND_BASE_URL="http://localhost:8001"
# LangGraph-compatible API URL (optional, uses local Next.js/nginx proxy by default)
NEXT_PUBLIC_LANGGRAPH_BASE_URL="http://localhost:8001/api"
```

## Project Structure

```
tests/
├── e2e/                    # E2E tests (Playwright, Chromium, mocked backend)
└── unit/                   # Unit tests (mirrors src/ layout)
src/
├── app/                    # Next.js App Router pages
│   ├── api/                # API routes
│   ├── showcase/           # Allowlisted public read-only demos
│   ├── workspace/          # Main workspace pages
│   └── mock/               # Mock/demo pages
├── components/             # React components
│   ├── ui/                 # Reusable UI components
│   ├── workspace/          # Workspace-specific components
│   ├── landing/            # Landing page components
│   └── ai-elements/        # AI-related UI elements
├── core/                   # Core business logic
│   ├── api/                # API client & data fetching
│   ├── artifacts/          # Artifact management
│   ├── config/              # App configuration
│   ├── i18n/               # Internationalization
│   ├── mcp/                # MCP integration
│   ├── messages/           # Message handling
│   ├── models/             # Data models & types
│   ├── settings/           # User settings
│   ├── skills/             # Skills system
│   ├── threads/            # Thread management
│   ├── todos/              # Todo system
│   └── utils/              # Utility functions
├── hooks/                  # Custom React hooks
├── lib/                    # Shared libraries & utilities
├── server/                 # Server-side code
│   └── better-auth/        # Authentication setup and session helpers
└── styles/                 # Global styles
```

## Scripts

| Command             | Description                           |
| ------------------- | ------------------------------------- |
| `pnpm dev`          | Start development server with Webpack |
| `pnpm build`        | Build for production                  |
| `pnpm start`        | Start production server               |
| `pnpm test`         | Run unit tests with Rstest            |
| `pnpm test:e2e`     | Run E2E tests with Playwright         |
| `pnpm format`       | Check formatting with Prettier        |
| `pnpm format:write` | Apply formatting with Prettier        |
| `pnpm lint`         | Run ESLint                            |
| `pnpm lint:fix`     | Fix ESLint issues                     |
| `pnpm typecheck`    | Run TypeScript type checking          |
| `pnpm check`        | Run both lint and typecheck           |

## Development Notes

HTML artifact previews keep an opaque iframe sandbox. Static sibling images,
responsive image sources, classic scripts, stylesheets, CSS imports and CSS
`url()` resources in the same thread's artifact route are fetched by the
authenticated parent and inlined as data URLs. Existing external
resources and external `<base>` URLs retain their browser behavior. Resource
preparation is capped at 32 resources, 4 MiB per resource, 16 MiB total, eight
nested CSS imports, 24 MiB of expanded references and ten seconds; unavailable or oversized resources show a
partial-preview notice. Switching artifacts cancels preparation and releases
the generated document Blob URL.
Resource 401 responses remain local to the partial preview; only the document
load uses the application's login-redirect policy. Preparation preserves the
original doctype (including its absence) and handles inline SVG styles.

This supports static generated reports rather than a complete website runtime.
ES module imports, resources created dynamically by JavaScript, `fetch()`/XHR,
iframes and navigation still follow opaque-origin browser restrictions and do
not receive the parent session. View source or download the files when a report
requires those features.

- Uses pnpm workspaces (see `packageManager` in package.json)
- Webpack is the default development bundler until the upstream Turbopack PostCSS worker leak is fixed in a stable Next.js release (#5132). Set `DEER_FLOW_DEV_BUNDLER=turbo` to opt in to Turbopack for local diagnosis, or `DEER_FLOW_DEV_BUNDLER=webpack` to select Webpack explicitly. Reconsider the default after the stable fix is verified on macOS arm64 and Linux.
- Environment validation can be skipped with `SKIP_ENV_VALIDATION=1` (useful for Docker)
- Backend API URLs are optional; nginx proxy is used by default in development

## License

MIT License. See [LICENSE](../LICENSE) for details.