Deploy guide · Bun

Deploy Bun in minutes.

Connect the repository, Railpack builds it, the service gets a domain with TLS. Databases from templates, usage drawn per minute from a prepaid balance, everything on EU nodes.

Start with GitHub See the CLI guide

terminal

$ npm i -g skiffly && skiffly login
$ cd my-bun-app && skiffly init
$ skiffly up
$ skiffly logs -f

What Railpack detects

Railpack inspects the repository and picks the build for Bun; most projects need no configuration. A Dockerfile in the repository always wins.

bun.lock / bun.lockb
package.json (start script)
bunfig.toml

Builder: Railpack (default)
Start command: bun run start

Port and $PORT

Skiffly injects PORT into every service and routes the public domain to it. Set the port in the service settings when your app listens on a fixed one; the default is 3000 for Bun, 8080 when nothing is set.

Listen on $PORT

Bun.serve({ port: Number(process.env.PORT ?? 3000), fetch })

PORT: 3000
SKIFFLY_PUBLIC_DOMAIN: <service>.skiffly.cloud

From a terminal

Install the CLI, link the directory, deploy. skiffly up builds the pushed HEAD of the current branch and streams the build logs; skiffly domain gives the service a *.skiffly.cloud address.

Or describe it once

.skiffly/skiffly.ts declares the service, its databases and the references between them. skiffly config plan shows the diff, skiffly config apply makes it so. The API mirrors railway/iac.

Config as code

.skiffly/skiffly.ts

// .skiffly/skiffly.ts
import { defineSkiffly, github, postgres, project, redis, service } from "@skiffly/config";

export default defineSkiffly(() => {
  const db = postgres("db");
  const cache = redis("cache");

  const web = service("api", {
    source: github("acme/api"),
    start: "bun run src/index.ts",
    port: 3000,
    healthcheck: "/",
    env: {
      DATABASE_URL: db.env.DATABASE_URL,
      REDIS_URL: cache.env.REDIS_URL,
    },
  });

  return project("api", { resources: [web, db, cache] });
});

Works with the templates you need

Deploy a database next to the Bun service and reference its variables: ${{Postgres.DATABASE_URL}} is wired on the private network, no public port.

Browse all templates

PostgreSQL 17The world's most advanced open-source relational database, with a persistent volume and DATABASE_URL pre-wired.Redis 7In-memory data store for caching, sessions and queues with append-only persistence.

Bun on Skiffly: common questions

How do I set environment variables for Bun?

In the service's Variables tab, with skiffly variables set KEY=value, or in .skiffly/skiffly.ts. Reference other services with ${{Postgres.DATABASE_URL}} and environment-wide values with ${{shared.NAME}}. Secrets are encrypted at rest.

Can I change the build or start command?

Yes. Settings → Build → Build command overrides Railpack's build step; Settings → Deploy → Start command replaces the start command. A monorepo sets a root directory so the build runs inside it.

How do I add Postgres or Redis?

Deploy the template into the same environment. It arrives with a volume, generated credentials and a connection URL you reference from the Bun service. Connect from your laptop with skiffly connect postgres.

Do I get preview environments per pull request?

Turn on PR previews on the project: every pull request gets its own copy of the environment on its own domain, removed when the PR is merged or closed. Forks are ignored.

What does a small Bun app cost?

A 512 MB / 0.25 vCPU service runs at about $7.75 a month, drawn per minute from your balance. Add Postgres with 512 MB / 0.25 vCPU and a 10 GB volume for about $9 more. The free tier runs one 512 MB service with App Sleeping at no cost.

Can the Bun service sleep when idle?

Turn on App Sleeping: after about 10 minutes without a request it scales to zero and wakes on the next one (2–10 s). CPU and memory are not billed while asleep; the volume is.

Deploy your Bun app today

Free tier without a card. Hobby from $5 with $5 of usage included.

Start with GitHub