---
title: HTML & static sites
description: Build static sites, landing pages, and web applications with Bun's bundler
---

Bun's bundler has first-class support for HTML. Build static sites, landing pages, and web applications with zero configuration: point Bun at your HTML file and it bundles the scripts, stylesheets, and assets the file references.

```html title="index.html" icon="file-code"
<!doctype html>
<html>
  <head>
    <link rel="stylesheet" href="./styles.css" />
    <script src="./app.ts" type="module"></script>
  </head>
  <body>
    <img src="./logo.png" />
  </body>
</html>
```

To get started, pass HTML files to `bun`.

```bash terminal icon="terminal"
bun ./index.html
```

```
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Press h + Enter to show shortcuts
```

With no configuration, Bun's development server provides:

- **Automatic Bundling** - Bundles and serves your HTML, JavaScript, and CSS
- **Multi-Entry Support** - Handles multiple HTML entry points and glob entry points
- **Modern JavaScript** - TypeScript & JSX support by default
- **Smart Configuration** - Reads `tsconfig.json` for paths, JSX options, and experimental decorators
- **Plugins** - Plugin support, including TailwindCSS
- **ESM & CommonJS** - Use ESM and CommonJS in your JavaScript, TypeScript, and JSX files
- **CSS Bundling & Minification** - Bundles CSS from `<link>` tags and `@import` statements
- **Asset Management** - Copies and hashes images and assets, and rewrites asset paths in JavaScript, CSS, and HTML

## Single Page Apps (SPA)

When you pass a single `.html` file to Bun, Bun uses it as a fallback route for all paths. This suits single page apps that use client-side routing:

```bash terminal icon="terminal"
bun index.html
```

```
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Press h + Enter to show shortcuts
```

Your React or other SPA works with no configuration. Routes like `/about` and `/users/123` serve the same HTML file, so your client-side router handles the navigation.

```html title="index.html" icon="file-code"
<!doctype html>
<html>
  <head>
    <title>My SPA</title>
    <script src="./app.tsx" type="module"></script>
  </head>
  <body>
    <div id="root"></div>
  </body>
</html>
```

## Multi-page apps (MPA)

Some projects have several separate routes or HTML files as entry points. To support multiple entry points, pass them all to `bun`:

```bash terminal icon="terminal"
bun ./index.html ./about.html
```

```txt
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Routes:
  / ./index.html
  /about ./about.html
Press h + Enter to show shortcuts
```

This serves:

- `index.html` at `/`
- `about.html` at `/about`

### Glob patterns

To specify multiple files, use a glob pattern that ends in `.html`:

```bash terminal icon="terminal"
bun ./**/*.html
```

```
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Routes:
  / ./index.html
  /about ./about.html
Press h + Enter to show shortcuts
```

### Path normalization

Bun chooses the base path from the longest common prefix among all the files.

```bash terminal icon="terminal"
bun ./index.html ./about/index.html ./about/foo/index.html
```

```
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Routes:
  / ./index.html
  /about ./about/index.html
  /about/foo ./about/foo/index.html
Press h + Enter to show shortcuts
```

## JavaScript, TypeScript, and JSX

Bun's transpiler natively implements JavaScript, TypeScript, and JSX support. See [loaders](/bundler/loaders).

<Note>Bun's transpiler is also used at runtime.</Note>

### ES Modules & CommonJS

You can use ESM and CommonJS in your JavaScript, TypeScript, and JSX files. Bun transpiles and bundles them automatically.

There is no pre-build or separate optimization step. It's all done at the same time.

See [module resolution](/runtime/module-resolution).

## CSS

Bun's CSS parser is also natively implemented (about 70,000 lines of Rust).

It's also a CSS bundler. You can use `@import` in your CSS files to import other CSS files.

For example:

<CodeGroup>

```css styles.css icon="file-code"
@import "./abc.css";

.container {
  background-color: blue;
}
```

```css abc.css icon="file-code"
body {
  background-color: red;
}
```

</CodeGroup>

This outputs:

```css styles.css icon="file-code"
body {
  background-color: red;
}

.container {
  background-color: blue;
}
```

### Referencing local assets in CSS

```css styles.css icon="file-code"
body {
  background-image: url("./logo.png");
}
```

Bun copies `./logo.png` to the output directory and rewrites the path in the CSS file to include a content hash.

```css styles.css icon="file-code"
body {
  background-image: url("./logo-[ABC123].png");
}
```

### Importing CSS in JavaScript

To associate a CSS file with a JavaScript file, import it from the JavaScript file.

```ts app.ts icon="/icons/typescript.svg"
import "./styles.css";
import "./more-styles.css";
```

This generates `./app.css` and `./app.js` in the output directory. All CSS files imported from JavaScript are bundled into a single CSS file per entry point. If you import the same CSS file from multiple JavaScript files, it is only included once in the output CSS file.

## Plugins

The dev server supports plugins.

### Tailwind CSS

To use TailwindCSS, install the `bun-plugin-tailwind` plugin:

```bash terminal icon="terminal"
# Or any npm client
bun install --dev bun-plugin-tailwind
```

Then, add the plugin to your `bunfig.toml`:

```toml title="bunfig.toml" icon="settings"
[serve.static]
plugins = ["bun-plugin-tailwind"]
```

Then, reference TailwindCSS in your HTML with a `<link>` tag, an `@import` in CSS, or an import in JavaScript.

<Tabs>
  <Tab title="index.html">

    ```html title="index.html" icon="file-code"
    <!-- Reference TailwindCSS in your HTML -->
    <link rel="stylesheet" href="tailwindcss" />
    ```

  </Tab>
  <Tab title="styles.css">

    ```css title="styles.css" icon="file-code"
    @import "tailwindcss";
    ```

  </Tab>
  <Tab title="app.ts">

    ```ts title="app.ts" icon="/icons/typescript.svg"
    import "tailwindcss";
    ```

  </Tab>
</Tabs>

<Info>Only one of these is necessary, not all three.</Info>

## Inline environment variables

Bun can replace `process.env.*` references in your JavaScript and TypeScript with their actual values at build time. Use this to inject configuration like API URLs or feature flags into your frontend code.

### Dev server (runtime)

To inline environment variables when using `bun ./index.html`, configure the `env` option in your `bunfig.toml`:

```toml title="bunfig.toml" icon="settings"
[serve.static]
env = "PUBLIC_*"  # only inline env vars starting with PUBLIC_ (recommended)
# env = "inline"  # inline all environment variables
# env = "disable" # disable env var replacement (default)
```

<Note>
  This only works with literal `process.env.FOO` references, not `import.meta.env` or indirect access like `const env =
  process.env; env.FOO`.

If an environment variable is not set, you may see runtime errors like `ReferenceError: process
  is not defined` in the browser.

</Note>

Then run the dev server:

```bash terminal icon="terminal"
PUBLIC_API_URL=https://api.example.com bun ./index.html
```

### Build for production

When building static HTML for production, use the `env` option to inline environment variables:

<Tabs>
  <Tab title="CLI">
    ```bash terminal icon="terminal"
    # Inline all environment variables
    bun build ./index.html --outdir=dist --env=inline

    # Only inline env vars with a specific prefix (recommended)
    bun build ./index.html --outdir=dist --env=PUBLIC_*
    ```

  </Tab>
  <Tab title="API">
    ```ts title="build.ts" icon="/icons/typescript.svg"
    // Inline all environment variables
    await Bun.build({
      entrypoints: ["./index.html"],
      outdir: "./dist",
      env: "inline", // [!code highlight]
    });

    // Only inline env vars with a specific prefix (recommended)
    await Bun.build({
      entrypoints: ["./index.html"],
      outdir: "./dist",
      env: "PUBLIC_*", // [!code highlight]
    });
    ```

  </Tab>
</Tabs>

### Example

Given this source file:

```ts title="app.ts" icon="/icons/typescript.svg"
const apiUrl = process.env.PUBLIC_API_URL;
console.log(`API URL: ${apiUrl}`);
```

And running with `PUBLIC_API_URL=https://api.example.com`:

```bash terminal icon="terminal"
PUBLIC_API_URL=https://api.example.com bun build ./index.html --outdir=dist --env=PUBLIC_*
```

The bundled output contains:

```js title="dist/app.js" icon="/icons/javascript.svg"
const apiUrl = "https://api.example.com";
console.log(`API URL: ${apiUrl}`);
```

## Echo console logs from browser to terminal

Bun's dev server can stream console logs from the browser to the terminal. To enable this, pass the `--console` CLI flag.

```bash terminal icon="terminal"
bun ./index.html --console
```

```
Bun v1.3.3
ready in 6.62ms
→ http://localhost:3000/
Press h + Enter to show shortcuts
```

Each call to `console.log` or `console.error` is broadcast to the terminal that started the server, so browser errors show up in the same place you run your server. This also helps AI agents that watch terminal output.

Internally, this reuses the existing WebSocket connection from hot module replacement (HMR) to send the logs.

## Edit files in the browser

Bun's frontend dev server supports Automatic Workspace Folders in Chrome DevTools, so you can save edits to files from the browser.

## Keyboard Shortcuts

While the server is running:

- `o + Enter` - Open in browser
- `c + Enter` - Clear console
- `q + Enter` (or `Ctrl+C`) - Quit server

## Build for Production

When you're ready to deploy, use `bun build` to create optimized production bundles:

<Tabs>
  <Tab title="CLI">
    ```bash terminal icon="terminal"
    bun build ./index.html --minify --outdir=dist
    ```
  </Tab>
  <Tab title="API">
    ```ts title="build.ts" icon="/icons/typescript.svg"
    await Bun.build({
      entrypoints: ["./index.html"],
      outdir: "./dist",
      minify: true,
    });
    ```
  </Tab>
</Tabs>

<Warning>
  Plugins are only supported through `Bun.build`'s API or through `bunfig.toml` with the frontend dev server, not
  through `bun build`'s CLI.
</Warning>

### Watch Mode

Run `bun build --watch` to watch for changes and rebuild automatically. This works well for library development.

<Info>You've never seen a watch mode this fast.</Info>

## Plugin API

For more control, configure the bundler through the JavaScript API and use Bun's built-in `HTMLRewriter` to preprocess HTML.

```ts title="build.ts" icon="/icons/typescript.svg"
await Bun.build({
  entrypoints: ["./index.html"],
  outdir: "./dist",
  minify: true,

  plugins: [
    {
      // A plugin that makes every HTML tag lowercase
      name: "lowercase-html-plugin",
      setup({ onLoad }) {
        const rewriter = new HTMLRewriter().on("*", {
          element(element) {
            element.tagName = element.tagName.toLowerCase();
          },
          text(element) {
            element.replace(element.text.toLowerCase());
          },
        });

        onLoad({ filter: /\.html$/ }, async args => {
          const html = await Bun.file(args.path).text();

          return {
            // Bun's bundler will scan the HTML for <script> tags, <link rel="stylesheet"> tags, and other assets
            // and bundle them automatically
            contents: rewriter.transform(html),
            loader: "html",
          };
        });
      },
    },
  ],
});
```

## What Gets Processed?

Bun automatically handles all common web assets:

- **Scripts** (`<script src>`) are run through Bun's JavaScript/TypeScript/JSX bundler
- **Stylesheets** (`<link rel="stylesheet">`) are run through Bun's CSS parser & bundler
- **Images** (`<img>`, `<picture>`) are copied and hashed
- **Media** (`<video>`, `<audio>`, `<source>`) are copied and hashed
- Any `<link>` tag with an `href` attribute pointing to a local file is rewritten to the new path, and hashed

Bun resolves all paths relative to your HTML file, so you can organize your project however you want.

<Warning>
**This is a work in progress**
- Need more plugins
- Need more configuration options for things like asset handling
- Need a way to configure CORS, headers, etc.

{/* todo: find the correct link to link to as this 404's and there isn't any similar files */}
{/* If you want to submit a PR, most of the code is [here](https://github.com/oven-sh/bun/blob/main/src/runtime/api/bun/html-rewriter.ts). You could even copy paste that file into your project and use it as a starting point. */}

</Warning>

## How this works

This is a small wrapper around Bun's support for [HTML imports](/bundler/fullstack) in JavaScript.

## Standalone HTML

You can bundle your entire frontend into a **single self-contained `.html` file** with no external dependencies using `--compile --target=browser`. All JavaScript, CSS, and images are inlined directly into the HTML.

```bash terminal icon="terminal"
bun build --compile --target=browser ./index.html --outdir=dist
```

Learn more in the [Standalone HTML docs](/bundler/standalone-html).

## Adding a backend to your frontend

To add a backend to your frontend, use the `routes` option in `Bun.serve`. See the [full-stack docs](/bundler/fullstack).
