Configuration

Environment variables (runtime)

Variable	Default	Description
PORT	3000	Server port
HOSTNAME	0.0.0.0	Server hostname
KEEP_ALIVE_TIMEOUT	—	HTTP keep-alive timeout (ms)
NBC_RUNTIME_DIR	binary’s directory	Where runtime files extract and .next/cache lives. Point at tmpfs (e.g. /tmp/app) for RAM-backed runtime files and read-only root filesystems.
NEXT_BUN_COMPILE_DEBUG	0	Set to 1 to log every resolver-hook decision. See Debug mode.

Environment variables (build time)

Variable	Default	Description
NEXT_ADAPTER_PATH	—	Enable the adapter without touching next.config: NEXT_ADAPTER_PATH=next-bun-compile next build
NBC_TARGET	host platform	Cross-compile target, e.g. bun-linux-x64. See Cross-compilation.
NEXT_BUN_COMPILE_VERBOSE	0	Set to 1 to print the alias-resolution table at build time.

next.config.ts options

adapterPath (required)

const nextConfig: NextConfig = {
  adapterPath: "next-bun-compile",
};

This makes next build produce the binary directly. output: "standalone" is not required (and not used) — the adapter assembles its own traced output tree from the build.

In monorepos or linked workspaces, Next resolves adapterPath from its own package location — resolve from the app dir instead:

import { createRequire } from "node:module";
const req = createRequire(process.cwd() + "/");

const nextConfig: NextConfig = {
  adapterPath: req.resolve("next-bun-compile"),
};

assetPrefix (optional, optimizes binary size)

If you set assetPrefix for a CDN, next-bun-compile detects it and skips embedding static assets in the binary — your CDN serves them instead. Only public/ files and runtime chunks get embedded.

const nextConfig: NextConfig = {
  adapterPath: "next-bun-compile",
  assetPrefix: "https://cdn.example.com",
};

You’ll need to upload .next/static/ to your CDN separately.

transpilePackages (optional, for packages with dynamic requires)

Some packages use dynamic require() calls internally that Turbopack can’t resolve at build time. Force them through the bundler instead:

const nextConfig: NextConfig = {
  adapterPath: "next-bun-compile",
  transpilePackages: ["pino", "pino-pretty"],
};

See the transpilePackages guide for when you need this.

Custom cache handlers

If you configure a custom cacheHandler, the in-memory page tiers turn themselves off automatically (revalidation events flow through your handler, which the memory tiers can’t observe) — every page request goes through Next exactly as it would under next start. Static assets are still served from memory.

Where the binary appears

./server next to the package.json of the project being built. In a monorepo, this is apps/<your-app>/server. Monorepo layouts are detected automatically.