Heroku buildpack for Bun runtime. Used in production at Lugg.

heroku buildpacks:set https://github.com/lugg/heroku-buildpack-bun

Your app must have a bun.lock or bun.lockb file in the root directory.

Pin the Bun version using either:

1. BUN_VERSION environment variable
2. .bun-version file in your repo root

# Via config var
heroku config:set BUN_VERSION=1.1.38

# Or via file
echo "1.1.38" > .bun-version

For monorepos with Bun workspaces, use --cwd in your Procfile to run from a subdirectory.

Heroku starts dynos from the repo root. Use --cwd to run from your app directory:

web: bun run --cwd apps/server src/index.ts
worker: bun run --cwd apps/server src/worker.ts
release: bun run --cwd apps/server db:migrate

That's it! The buildpack runs bun install from root, which resolves all workspace dependencies.

my-monorepo/
├── apps/
│   └── server/
│       ├── src/index.ts
│       ├── src/worker.ts
│       └── package.json
├── packages/
│   └── shared/
│       └── package.json
├── package.json            # workspaces: ["apps/*", "packages/*"]
├── bun.lock
└── Procfile                # at root, uses --cwd

Only needed if your app subdirectory has build, heroku-prebuild, or heroku-postbuild scripts:

heroku config:set BUN_APP_PATH=apps/server

This runs those lifecycle scripts from apps/server/ instead of root.

The buildpack runs these scripts if present in your package.json (or BUN_APP_PATH/package.json for monorepos):

1. bun install --frozen-lockfile
2. bun run heroku-prebuild
3. bun run build
4. bun run heroku-postbuild

Create a Procfile at your repo root to define process types:

web: bun run src/index.ts
worker: bun run src/worker.ts
release: bun run db:migrate

For monorepos, use --cwd to run from a subdirectory (see above).

MIT