Single-file executable

Bun’s bundler implements a --compile flag for generating a standalone binary from a TypeScript or JavaScript file.

CLI
JavaScript

terminal

bun build ./cli.ts --compile --outfile mycli

build.ts

await Bun.build({
  entrypoints: ["./cli.ts"],
  compile: {
    outfile: "./mycli",
  },
});

cli.ts

console.log("Hello world!");

This bundles cli.ts into an executable you can run directly:

terminal

./mycli

Hello world!

All imported files and packages are bundled into the executable, along with a copy of the Bun runtime. All built-in Bun and Node.js APIs are supported.

Cross-compile to other platforms

Use the --target flag to compile your standalone executable for a different operating system, architecture, or version of Bun than the machine you’re running bun build on. To build for Linux x64 (most servers):

CLI
JavaScript

terminal

bun build --compile --target=bun-linux-x64 ./index.ts --outfile myapp

# To support CPUs from before 2013, use the baseline version (nehalem)
bun build --compile --target=bun-linux-x64-baseline ./index.ts --outfile myapp

# To explicitly only support CPUs from 2013 and later, use the modern version (haswell)
# modern is faster, but baseline is more compatible.
bun build --compile --target=bun-linux-x64-modern ./index.ts --outfile myapp

build.ts

// Standard Linux x64
await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    target: "bun-linux-x64",
    outfile: "./myapp",
  },
});

// Baseline (pre-2013 CPUs)
await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    target: "bun-linux-x64-baseline",
    outfile: "./myapp",
  },
});

// Modern (2013+ CPUs, faster)
await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    target: "bun-linux-x64-modern",
    outfile: "./myapp",
  },
});

To build for Linux ARM64 (for example, Graviton or Raspberry Pi):

CLI
JavaScript

terminal

# Note: the default architecture is x64 if no architecture is specified.
bun build --compile --target=bun-linux-arm64 ./index.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    target: "bun-linux-arm64",
    outfile: "./myapp",
  },
});

To build for Windows x64:

CLI
JavaScript

terminal

bun build --compile --target=bun-windows-x64 ./path/to/my/app.ts --outfile myapp

# To support CPUs from before 2013, use the baseline version (nehalem)
bun build --compile --target=bun-windows-x64-baseline ./path/to/my/app.ts --outfile myapp

# To explicitly only support CPUs from 2013 and later, use the modern version (haswell)
bun build --compile --target=bun-windows-x64-modern ./path/to/my/app.ts --outfile myapp

# note: if no .exe extension is provided, Bun adds it automatically for Windows executables

build.ts

// Standard Windows x64
await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    target: "bun-windows-x64",
    outfile: "./myapp", // .exe added automatically
  },
});

// Baseline or modern variants
await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    target: "bun-windows-x64-baseline",
    outfile: "./myapp",
  },
});

To build for Windows arm64:

CLI
JavaScript

terminal

bun build --compile --target=bun-windows-arm64 ./path/to/my/app.ts --outfile myapp

# note: if no .exe extension is provided, Bun adds it automatically for Windows executables

build.ts

await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    target: "bun-windows-arm64",
    outfile: "./myapp", // .exe added automatically
  },
});

To build for macOS arm64:

CLI
JavaScript

terminal

bun build --compile --target=bun-darwin-arm64 ./path/to/my/app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    target: "bun-darwin-arm64",
    outfile: "./myapp",
  },
});

To build for macOS x64:

CLI
JavaScript

terminal

bun build --compile --target=bun-darwin-x64 ./path/to/my/app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    target: "bun-darwin-x64",
    outfile: "./myapp",
  },
});

Supported targets

The segments of the --target value can appear in any order, as long as they’re delimited by -.

—target	Operating System	Architecture	Modern	Baseline	Libc
bun-linux-x64	Linux	x64	✅	✅	glibc
bun-linux-arm64	Linux	arm64	✅	N/A	glibc
bun-windows-x64	Windows	x64	✅	✅	-
bun-windows-arm64	Windows	arm64	✅	N/A	-
bun-darwin-x64	macOS	x64	✅	✅	-
bun-darwin-arm64	macOS	arm64	✅	N/A	-
bun-linux-x64-musl	Linux	x64	✅	✅	musl
bun-linux-arm64-musl	Linux	arm64	✅	N/A	musl

On x64 platforms, Bun uses SIMD optimizations that require a CPU with AVX2 instructions. The -baseline build of Bun is for older CPUs without them. The Bun installer detects which version to use, but when cross-compiling you might not know the target CPU. This mostly matters on Windows x64 and Linux x64, rarely on Darwin x64. If you or your users see "Illegal instruction" errors, you might need to use the baseline version.

Build-time constants

Use the --define flag to inject build-time constants into your executable, such as version numbers, build timestamps, or configuration values:

CLI
JavaScript

terminal

bun build --compile --define BUILD_VERSION='"1.2.3"' --define BUILD_TIME='"2024-01-15T10:30:00Z"' src/cli.ts --outfile mycli

build.ts

await Bun.build({
  entrypoints: ["./src/cli.ts"],
  compile: {
    outfile: "./mycli",
  },
  define: {
    BUILD_VERSION: JSON.stringify("1.2.3"),
    BUILD_TIME: JSON.stringify("2024-01-15T10:30:00Z"),
  },
});

Bun inlines these constants into the binary at build time, so they cost nothing at runtime and enable dead code elimination.

For more examples and patterns, see the Build-time constants guide.

Deploying to production

Compiled executables reduce memory usage and improve Bun’s start time. Normally, Bun reads and transpiles JavaScript and TypeScript files on import and require. This is part of what makes so much of Bun “just work”, but it’s not free: reading files from disk, resolving paths, parsing, transpiling, and printing source code costs time and memory. Compiled executables move that cost from runtime to build time. When deploying to production, we recommend the following:

CLI
JavaScript

terminal

bun build --compile --minify --sourcemap ./path/to/my/app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    outfile: "./myapp",
  },
  minify: true,
  sourcemap: "linked",
});

Bytecode compilation

To improve startup time, enable bytecode compilation:

CLI
JavaScript

terminal

bun build --compile --minify --sourcemap --bytecode ./path/to/my/app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./path/to/my/app.ts"],
  compile: {
    outfile: "./myapp",
  },
  minify: true,
  sourcemap: "linked",
  bytecode: true,
});

Using bytecode compilation, tsc starts 2x faster:

Bytecode compilation moves parsing overhead for large input files from runtime to bundle time. Your app starts faster, in exchange for making the bun build command a little slower. It doesn’t obscure source code.

Bytecode compilation supports both cjs and esm formats when used with --compile.

What do these flags do?

The --minify argument reduces the size of the transpiled output code. For a large application, this can save megabytes of space. For smaller applications, it might still improve start time a little. The --sourcemap argument embeds a sourcemap compressed with zstd, so that errors & stacktraces point to their original locations instead of the transpiled location. Bun decompresses & resolves the sourcemap automatically when an error occurs. The --bytecode argument enables bytecode compilation. Every time you run JavaScript code in Bun, JavaScriptCore (the engine) compiles your source code into bytecode. --bytecode moves that parsing work from runtime to bundle time, which shortens startup.

Embedding runtime arguments

--compile-exec-argv="args" - Embed runtime arguments, available at runtime in process.execArgv:

CLI
JavaScript

terminal

bun build --compile --compile-exec-argv="--smol --user-agent=MyBot" ./app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./app.ts"],
  compile: {
    execArgv: ["--smol", "--user-agent=MyBot"],
    outfile: "./myapp",
  },
});

app.ts

// In the compiled app
console.log(process.execArgv); // ["--smol", "--user-agent=MyBot"]

Runtime arguments via `BUN_OPTIONS`

Standalone executables read the BUN_OPTIONS environment variable, so you can pass runtime flags without recompiling:

terminal

# Enable CPU profiling on a compiled executable
BUN_OPTIONS="--cpu-prof" ./myapp

# Enable heap profiling with markdown output
BUN_OPTIONS="--heap-prof-md" ./myapp

# Combine multiple flags
BUN_OPTIONS="--smol --cpu-prof-md" ./myapp

Automatic config loading

Standalone executables can automatically load configuration files from the directory where they are run. By default:

tsconfig.json and package.json loading is disabled — these are typically only needed at development time, and the bundler already uses them when compiling
.env and bunfig.toml loading is enabled — these often contain runtime configuration that may vary per deployment

In a future version of Bun, .env and bunfig.toml may also be disabled by default for more deterministic behavior.

Enabling config loading at runtime

If your executable needs to read tsconfig.json or package.json at runtime, opt in with these flags:

terminal

# Enable runtime loading of tsconfig.json
bun build --compile --compile-autoload-tsconfig ./app.ts --outfile myapp

# Enable runtime loading of package.json
bun build --compile --compile-autoload-package-json ./app.ts --outfile myapp

# Enable both
bun build --compile --compile-autoload-tsconfig --compile-autoload-package-json ./app.ts --outfile myapp

Disabling config loading at runtime

To disable .env or bunfig.toml loading for deterministic execution:

CLI
JavaScript

terminal

# Disable .env loading
bun build --compile --no-compile-autoload-dotenv ./app.ts --outfile myapp

# Disable bunfig.toml loading
bun build --compile --no-compile-autoload-bunfig ./app.ts --outfile myapp

# Disable all config loading
bun build --compile --no-compile-autoload-dotenv --no-compile-autoload-bunfig ./app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./app.ts"],
  compile: {
    // tsconfig.json and package.json are disabled by default
    autoloadTsconfig: true, // Enable tsconfig.json loading
    autoloadPackageJson: true, // Enable package.json loading

    // .env and bunfig.toml are enabled by default
    autoloadDotenv: false, // Disable .env loading
    autoloadBunfig: false, // Disable bunfig.toml loading
    outfile: "./myapp",
  },
});

Act as the Bun CLI

New in Bun v1.2.16

Set the BUN_BE_BUN=1 environment variable to run a standalone executable as if it were the bun CLI itself. The executable ignores its bundled entrypoint and exposes the full bun CLI instead. For example, consider an executable compiled from this script:

terminal

echo "console.log(\"you shouldn't see this\");" > such-bun.js
bun build --compile ./such-bun.js

[3ms] bundle 1 modules
[89ms] compile such-bun

Normally, running ./such-bun with arguments executes the script.

terminal

# Executable runs its own entrypoint by default
./such-bun install

you shouldn't see this

However, with the BUN_BE_BUN=1 environment variable, it acts like the bun binary:

terminal

# With the env var, the executable acts like the `bun` CLI
BUN_BE_BUN=1 ./such-bun install

bun install v1.2.16-canary.1 (1d1db811)
Checked 63 installs across 64 packages (no changes) [5.00ms]

CLI tools built on top of Bun can use this to install packages, bundle dependencies, or run other files without downloading a separate binary or installing Bun.

Full-stack executables

New in Bun v1.2.17

The --compile flag can create a standalone executable that contains both server and client code, which suits full-stack applications. When you import an HTML file in your server code, Bun bundles the frontend assets (JavaScript, CSS, and so on) and embeds them into the executable.

import { serve } from "bun";
import index from "./index.html";

const server = serve({
  routes: {
    "/": index,
    "/api/hello": { GET: () => Response.json({ message: "Hello from API" }) },
  },
});

console.log(`Server running at http://localhost:${server.port}`);

To build this into a single executable:

CLI
JavaScript

terminal

bun build --compile ./server.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./server.ts"],
  compile: {
    outfile: "./myapp",
  },
});

This creates a self-contained binary that includes:

Your server code
The Bun runtime
All frontend assets (HTML, CSS, JavaScript)
Any npm packages used by your server

The result is a single file you can deploy anywhere without installing Node.js, Bun, or any dependencies:

terminal

./myapp

Bun serves the frontend assets with the correct MIME types and cache headers. The HTML import is replaced with a manifest object that Bun.serve uses to serve the pre-bundled assets. For more on building full-stack applications, see the full-stack guide.

Worker

To use workers in a standalone executable, add the worker’s entrypoint to the build:

CLI
JavaScript

terminal

bun build --compile ./index.ts ./my-worker.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./index.ts", "./my-worker.ts"],
  compile: {
    outfile: "./myapp",
  },
});

Then, reference the worker in your code:

index.ts

console.log("Hello from Bun!");

// Any of these will work:
new Worker("./my-worker.ts");
new Worker(new URL("./my-worker.ts", import.meta.url));
new Worker(new URL("./my-worker.ts", import.meta.url).href);

When you add multiple entrypoints to a standalone executable, each is bundled separately into the executable. We may eventually detect statically-known paths in new Worker(path) and bundle them automatically, but for now you need to list the worker file as an entrypoint, as in the earlier example. If you use a relative path to a file not included in the standalone executable, Bun loads that path from disk relative to the process’s current working directory, and errors if it doesn’t exist.

SQLite

You can use bun:sqlite imports with bun build --compile. By default, the database is resolved relative to the current working directory of the process.

index.ts

import db from "./my.db" with { type: "sqlite" };

console.log(db.query("select * from users LIMIT 1").get());

That means if the executable is at /usr/bin/hello and the user’s terminal is in /home/me/Desktop, Bun looks for /home/me/Desktop/my.db.

terminal

cd /home/me/Desktop
./hello

Embed assets & files

Standalone executables can embed files directly into the binary, so a single executable can ship images, JSON configs, templates, or any other assets your application needs.

How it works

Use the with { type: "file" } import attribute to embed a file:

index.ts

import icon from "./icon.png" with { type: "file" };

console.log(icon);
// During development: "./icon.png"
// After compilation: "$bunfs/icon-a1b2c3d4.png" (internal path)

The import returns a path string that points to the embedded file. At build time, Bun:

Reads the file contents
Embeds the data into the executable
Replaces the import with an internal path (prefixed with $bunfs/)

You can then read this embedded file using Bun.file() or Node.js fs APIs.

Reading embedded files with Bun.file()

Bun.file() is the recommended way to read embedded files:

index.ts

import icon from "./icon.png" with { type: "file" };
import { file } from "bun";

// Get file contents as different types
const bytes = await file(icon).arrayBuffer(); // ArrayBuffer
const text = await file(icon).text(); // string (for text files)
const blob = file(icon); // Blob

// Stream the file in a response
export default {
  fetch(req) {
    return new Response(file(icon), {
      headers: { "Content-Type": "image/png" },
    });
  },
};

Reading embedded files with Node.js fs

Embedded files work with the Node.js file system APIs:

index.ts

import icon from "./icon.png" with { type: "file" };
import config from "./config.json" with { type: "file" };
import { readFileSync, promises as fs } from "node:fs";

// Synchronous read
const iconBuffer = readFileSync(icon);

// Async read
const configData = await fs.readFile(config, "utf-8");
const parsed = JSON.parse(configData);

// Check file stats
const stats = await fs.stat(icon);
console.log(`Icon size: ${stats.size} bytes`);

Practical examples

Embedding a JSON config file

index.ts

import configPath from "./default-config.json" with { type: "file" };
import { file } from "bun";

// Load the embedded default configuration
const defaultConfig = await file(configPath).json();

// Merge with user config if it exists
const userConfig = await file("./user-config.json")
  .json()
  .catch(() => ({}));
const config = { ...defaultConfig, ...userConfig };

Serving static assets in an HTTP server

Use static routes in Bun.serve() for efficient static file serving:

server.ts

import favicon from "./favicon.ico" with { type: "file" };
import logo from "./logo.png" with { type: "file" };
import styles from "./styles.css" with { type: "file" };
import { file, serve } from "bun";

serve({
  static: {
    "/favicon.ico": file(favicon),
    "/logo.png": file(logo),
    "/styles.css": file(styles),
  },
  fetch(req) {
    return new Response("Not found", { status: 404 });
  },
});

Bun automatically handles Content-Type headers and caching for static routes.

Embedding templates

index.ts

import templatePath from "./email-template.html" with { type: "file" };
import { file } from "bun";

async function sendWelcomeEmail(user: { name: string; email: string }) {
  const template = await file(templatePath).text();
  const html = template.replace("{{name}}", user.name).replace("{{email}}", user.email);

  // Send email with the rendered template...
}

Embedding binary files

index.ts

import wasmPath from "./processor.wasm" with { type: "file" };
import fontPath from "./font.ttf" with { type: "file" };
import { file } from "bun";

// Load a WebAssembly module
const wasmBytes = await file(wasmPath).arrayBuffer();
const wasmModule = await WebAssembly.instantiate(wasmBytes);

// Read binary font data
const fontData = await file(fontPath).bytes();

Embed SQLite databases

To embed a SQLite database into the compiled executable, set type: "sqlite" in the import attribute and the embed attribute to "true". The database file must already exist on disk. Then, import it in your code:

index.ts

import myEmbeddedDb from "./my.db" with { type: "sqlite", embed: "true" };

console.log(myEmbeddedDb.query("select * from users LIMIT 1").get());

Finally, compile it into a standalone executable:

terminal

bun build --compile ./index.ts --outfile mycli

The database file must exist on disk when you run bun build --compile. The embed: "true" attribute tells the bundler to include the database contents inside the compiled executable. When running normally with bun run, the database file is loaded from disk just like a regular SQLite import.

In the compiled executable, the embedded database is read-write, but all changes are lost when the executable exits (since it’s stored in memory).

Embed N-API Addons

You can embed .node files into executables.

index.ts

const addon = require("./addon.node");

console.log(addon.hello());

If you’re using @mapbox/node-pre-gyp or similar tools, the .node file must be required directly or it won’t bundle correctly.

Embed directories

To embed a directory with bun build --compile, include file patterns in your build:

CLI
JavaScript

terminal

bun build --compile ./index.ts ./public/**/*.png

build.ts

import { Glob } from "bun";

// Expand glob pattern to file list
const glob = new Glob("./public/**/*.png");
const pngFiles = Array.from(glob.scanSync("."));

await Bun.build({
  entrypoints: ["./index.ts", ...pngFiles],
  compile: {
    outfile: "./myapp",
  },
});

Then, you can reference the files in your code:

index.ts

import icon from "./public/assets/icon.png" with { type: "file" };
import { file } from "bun";

export default {
  fetch(req) {
    // Embedded files can be streamed from Response objects
    return new Response(file(icon));
  },
};

This is a workaround, and we expect to replace it with a more direct API.

Detecting standalone mode at runtime

Use Bun.isStandaloneExecutable to check whether the current process is running from a compiled binary:

index.ts

if (Bun.isStandaloneExecutable) {
  // Running from `bun build --compile` output
} else {
  // Running via `bun <file>` or as a library
}

Unlike Bun.embeddedFiles.length > 0, this check does not allocate Blob objects for each embedded file, so it is safe to call at startup in binaries that embed large assets.

Listing embedded files

Bun.embeddedFiles exposes all embedded files as Blob objects:

index.ts

import "./icon.png" with { type: "file" };
import "./data.json" with { type: "file" };
import "./template.html" with { type: "file" };
import { embeddedFiles } from "bun";

// List all embedded files
for (const blob of embeddedFiles) {
  console.log(`${blob.name} - ${blob.size} bytes`);
}
// Output:
//   icon-a1b2c3d4.png - 4096 bytes
//   data-e5f6g7h8.json - 256 bytes
//   template-i9j0k1l2.html - 1024 bytes

Each item in Bun.embeddedFiles is a Blob with a name property:

embeddedFiles: ReadonlyArray<Blob>;

Use it to serve every embedded asset through static routes:

server.ts

import "./public/favicon.ico" with { type: "file" };
import "./public/logo.png" with { type: "file" };
import "./public/styles.css" with { type: "file" };
import { embeddedFiles, serve } from "bun";

// Build static routes from all embedded files
const staticRoutes: Record<string, Blob> = {};
for (const blob of embeddedFiles) {
  // Remove hash from filename: "icon-a1b2c3d4.png" -> "icon.png"
  const name = blob.name.replace(/-[a-f0-9]+\./, ".");
  staticRoutes[`/${name}`] = blob;
}

serve({
  static: staticRoutes,
  fetch(req) {
    return new Response("Not found", { status: 404 });
  },
});

Bun.embeddedFiles excludes bundled source code (.ts, .js, etc.) to help protect your application’s source.

Content hash

By default, embedded files have a content hash appended to their name, which helps with cache invalidation when you serve them from a URL or CDN. To keep the original name instead, configure asset naming:

CLI
JavaScript

terminal

bun build --compile --asset-naming="[name].[ext]" ./index.ts

build.ts

await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    outfile: "./myapp",
  },
  naming: {
    asset: "[name].[ext]",
  },
});

Minification

To trim down the size of the executable, enable minification:

CLI
JavaScript

terminal

bun build --compile --minify ./index.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    outfile: "./myapp",
  },
  minify: true, // Enable all minification
});

// Or granular control:
await Bun.build({
  entrypoints: ["./index.ts"],
  compile: {
    outfile: "./myapp",
  },
  minify: {
    whitespace: true,
    syntax: true,
    identifiers: true,
  },
});

This uses Bun’s minifier to reduce the code size. Overall though, Bun’s binary is still way too big and we need to make it smaller.

Windows-specific flags

When compiling a standalone executable on Windows, platform-specific options customize metadata on the generated .exe file:

CLI
JavaScript

terminal

# Custom icon
bun build --compile --windows-icon=path/to/icon.ico ./app.ts --outfile myapp

# Hide console window (for GUI apps)
bun build --compile --windows-hide-console ./app.ts --outfile myapp

build.ts

await Bun.build({
  entrypoints: ["./app.ts"],
  compile: {
    outfile: "./myapp",
    windows: {
      icon: "./path/to/icon.ico",
      hideConsole: true,
      // Additional Windows metadata:
      title: "My Application",
      publisher: "My Company",
      version: "1.0.0",
      description: "A standalone Windows application",
      copyright: "Copyright 2024",
    },
  },
});

Available Windows options:

icon - Path to .ico file for the executable icon
hideConsole - Disable the background terminal (for GUI apps)
title - Application title in file properties
publisher - Publisher name in file properties
version - Version string in file properties
description - Description in file properties
copyright - Copyright notice in file properties

These flags cannot be used when cross-compiling because they depend on Windows APIs.

Code signing on macOS

To codesign a standalone executable on macOS (which fixes Gatekeeper warnings), use the codesign command.

terminal

codesign --deep --force -vvvv --sign "XXXXXXXXXX" ./myapp

We recommend including an entitlements.plist file with JIT permissions.

info.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>com.apple.security.cs.allow-jit</key>
    <true/>
    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
    <true/>
    <key>com.apple.security.cs.disable-executable-page-protection</key>
    <true/>
    <key>com.apple.security.cs.allow-dyld-environment-variables</key>
    <true/>
    <key>com.apple.security.cs.disable-library-validation</key>
    <true/>
</dict>
</plist>

To codesign with JIT support, pass the --entitlements flag to codesign.

terminal

codesign --deep --force -vvvv --sign "XXXXXXXXXX" --entitlements entitlements.plist ./myapp

After codesigning, verify the executable:

terminal

codesign -vvv --verify ./myapp
./myapp: valid on disk
./myapp: satisfies its Designated Requirement

Codesign support requires Bun v1.2.4 or newer.

Code splitting

Standalone executables support code splitting. Use --compile with --splitting to create an executable that loads code-split chunks at runtime.

CLI
JavaScript

terminal

bun build --compile --splitting ./src/entry.ts --outdir ./build

build.ts

await Bun.build({
  entrypoints: ["./src/entry.ts"],
  compile: true,
  splitting: true,
  outdir: "./build",
});

console.log("Entrypoint loaded");
const lazy = await import("./lazy.ts");
lazy.hello();

terminal

./build/entry

Entrypoint loaded
Lazy module loaded

Using plugins

Plugins work with standalone executables; use them to transform files during the build:

build.ts

import type { BunPlugin } from "bun";

const envPlugin: BunPlugin = {
  name: "env-loader",
  setup(build) {
    build.onLoad({ filter: /\.env\.json$/ }, async args => {
      // Transform .env.json files into validated config objects
      const env = await Bun.file(args.path).json();

      return {
        contents: `export default ${JSON.stringify(env)};`,
        loader: "js",
      };
    });
  },
};

await Bun.build({
  entrypoints: ["./cli.ts"],
  compile: {
    outfile: "./mycli",
  },
  plugins: [envPlugin],
});

Example use case - embedding environment config at build time:

cli.ts

import config from "./config.env.json";

console.log(`Running in ${config.environment} mode`);
console.log(`API endpoint: ${config.apiUrl}`);

Plugins can perform any transformation: compile YAML/TOML configs, inline SQL queries, generate type-safe API clients, or preprocess templates. See the plugin documentation.

Unsupported CLI arguments

The --compile flag can only accept a single entrypoint at a time and does not support the following flags:

--outdir — use outfile instead (except when using with --splitting).
--public-path
--target=node
--target=browser (without HTML entrypoints — see Standalone HTML for --compile --target=browser with .html files)
--no-bundle - Bun always bundles everything into the executable.

API reference

The compile option in Bun.build() accepts three forms:

types

interface BuildConfig {
  entrypoints: string[];
  compile: boolean | Bun.Build.Target | CompileBuildOptions;
  // ... other BuildConfig options (minify, sourcemap, define, plugins, etc.)
}

interface CompileBuildOptions {
  target?: Bun.Build.Target; // Cross-compilation target
  outfile?: string; // Output executable path
  execArgv?: string[]; // Runtime arguments (process.execArgv)
  autoloadTsconfig?: boolean; // Load tsconfig.json (default: false)
  autoloadPackageJson?: boolean; // Load package.json (default: false)
  autoloadDotenv?: boolean; // Load .env files (default: true)
  autoloadBunfig?: boolean; // Load bunfig.toml (default: true)
  windows?: {
    icon?: string; // Path to .ico file
    hideConsole?: boolean; // Hide console window
    title?: string; // Application title
    publisher?: string; // Publisher name
    version?: string; // Version string
    description?: string; // Description
    copyright?: string; // Copyright notice
  };
}

Usage forms:

// Simple boolean - compile for current platform (uses entrypoint name as output)
compile: true

// Target string - cross-compile (uses entrypoint name as output)
compile: "bun-linux-x64"

// Full options object - specify outfile and other options
compile: {
  target: "bun-linux-x64",
  outfile: "./myapp",
}

Supported targets

Bun.Build.Target

type Target =
  | "bun-darwin-x64"
  | "bun-darwin-x64-baseline"
  | "bun-darwin-arm64"
  | "bun-linux-x64"
  | "bun-linux-x64-baseline"
  | "bun-linux-x64-modern"
  | "bun-linux-arm64"
  | "bun-linux-x64-musl"
  | "bun-linux-arm64-musl"
  | "bun-windows-x64"
  | "bun-windows-x64-baseline"
  | "bun-windows-x64-modern"
  | "bun-windows-arm64";

Complete example

build.ts

import type { BunPlugin } from "bun";

const myPlugin: BunPlugin = {
  name: "my-plugin",
  setup(build) {
    // Plugin implementation
  },
};

const result = await Bun.build({
  entrypoints: ["./src/cli.ts"],
  compile: {
    target: "bun-linux-x64",
    outfile: "./dist/mycli",
    execArgv: ["--smol"],
    autoloadDotenv: false,
    autoloadBunfig: false,
  },
  minify: true,
  sourcemap: "linked",
  bytecode: true,
  define: {
    "process.env.NODE_ENV": JSON.stringify("production"),
    VERSION: JSON.stringify("1.0.0"),
  },
  plugins: [myPlugin],
});

if (result.success) {
  console.log("Build successful:", result.outputs[0].path);
}

​Cross-compile to other platforms

​Supported targets

​Build-time constants

​Deploying to production

​Bytecode compilation

​What do these flags do?

​Embedding runtime arguments

​Runtime arguments via BUN_OPTIONS

​Automatic config loading

​Enabling config loading at runtime

​Disabling config loading at runtime

​Act as the Bun CLI

​Full-stack executables

​Worker

​SQLite

​Embed assets & files

​How it works

​Reading embedded files with Bun.file()

​Reading embedded files with Node.js fs

​Practical examples

​Embedding a JSON config file

​Serving static assets in an HTTP server

​Embedding templates

​Embedding binary files

​Embed SQLite databases

​Embed N-API Addons

​Embed directories

​Detecting standalone mode at runtime

​Listing embedded files

​Content hash

​Minification

​Windows-specific flags

​Code signing on macOS

​Code splitting

​Using plugins

​Unsupported CLI arguments

​API reference

​Supported targets

​Complete example

Cross-compile to other platforms

Supported targets

Build-time constants

Deploying to production

Bytecode compilation

What do these flags do?

Embedding runtime arguments

Runtime arguments via `BUN_OPTIONS`

Automatic config loading

Enabling config loading at runtime

Disabling config loading at runtime

Act as the Bun CLI

Full-stack executables

Worker

SQLite

Embed assets & files

How it works

Reading embedded files with Bun.file()

Reading embedded files with Node.js fs

Practical examples

Embedding a JSON config file

Serving static assets in an HTTP server

Embedding templates

Embedding binary files

Embed SQLite databases

Embed N-API Addons

Embed directories

Detecting standalone mode at runtime

Listing embedded files

Content hash

Minification

Windows-specific flags

Code signing on macOS

Code splitting

Using plugins

Unsupported CLI arguments

API reference

Supported targets

Complete example