Bundler

Decide whether you need a bundle

• Server-side TypeScript under Bun: direct execution may be enough.
• Browser code: bundle, split, and process assets.
• Single-file CLI or service: bundling simplifies distribution, subject to dynamic assets and native dependencies.
• Framework application: keep the framework's official build command unless it explicitly supports Bun's bundler.

CLI

bun build ./src/index.ts --outdir ./dist --target bun
bun build ./src/browser.tsx --outdir ./dist --target browser --splitting
bun build ./src/cli.ts --outfile ./dist/cli.js --target node --minify --sourcemap

JavaScript API

const result = await Bun.build({
  entrypoints: ['./src/index.ts'],
  outdir: './dist',
  target: 'bun',
  minify: true,
  sourcemap: 'linked',
});

if (!result.success) {
  for (const log of result.logs) console.error(log);
  process.exit(1);
}

Target matrix

Mark packages as external when they should stay outside the bundle, then ensure the deployment environment provides them. Native binaries and dynamic runtime loading need explicit verification.

Single-file executables

Compile a CLI, agent tool, or small fixed-platform service into a standalone executable:

bun build src/index.ts \
  --compile \
  --target=bun-linux-x64 \
  --outfile=dist/service

Cross-compilation is not target-platform validation. Start and test dynamic libraries, CA certificates, timezone data, subprocesses, external files, and native dependencies on the target OS and CPU. The project still owns signing, SBOMs, and release verification.

bun build ./src/index.ts --outdir ./dist --target bun --sourcemap
bun ./dist/index.js

Run the output on the same OS, architecture, and Bun version as production. A successful build is not a runtime test.

Official references: Bundler and single-file executables.