Node.js and Bun backends

Deploy a Express app on Enzonic

Express apps deploy as they run on your machine: Deploy installs dependencies, runs your build script if you have one and starts the server. Koa is detected the same way.

Deploy Express Docs

At a glance

What Enzonic Deploy does with a Express project when you connect it. You can override any of it in the project settings.

Language: JavaScript / TypeScript
Detected from: express or koa in dependencies; A start script, a main field, or server.js / index.js / app.js / src/index.js / server.mjs / index.mjs
Build command: Your build script, if any
Output: The project folder
Runs as: Server

Dependencies install with the package manager your lockfile names: npm ci, pnpm install --frozen-lockfile, yarn install --immutable (Berry) or --frozen-lockfile, or bun install --frozen-lockfile. Node.js 18, 20, 22 and 24 are available. Deploy reads engines.node in package.json, then .nvmrc or .node-version, and uses Node.js 22 when nothing pins a version.

How it runs

Server
Always: your start command with PORT set.

Deploy Express step by step

1Read the port from process.env.PORT.
2Connect the repository and deploy.

index.js

import express from 'express';

const app = express();
app.use(express.json());
app.get('/', (req, res) => res.send('Hello from Enzonic'));

app.listen(process.env.PORT ?? 3000);

Connect a database to Express

Create a database on Enzonic Databases (or from the project's settings) and its connection string is added to the project's environment variables. This example uses PostgreSQL.

routes/posts.js

import pg from 'pg';

const pool = new pg.Pool({ connectionString: process.env.DATABASE_URL });

export async function listPosts(req, res) {
  const { rows } = await pool.query('select id, title from posts limit 20');
  res.json(rows);
}

Postgres projects get two variables: DATABASE_URL through the connection pooler for the app, and DATABASE_URL_UNPOOLED for migrations.

PostgreSQL on Enzonic Databases Every database engine

Things to know

If package.json has neither a start script nor a main field, and none of the usual entry files exist, the build stops with "add \"start\" to package.json".

Plan limits that matter here

From the live plan data. Every plan includes previews for each branch, instant rollback, environment variables and logs.

Plan limits that matter for Express
Limit	Free	Pro
Build minutes	3,000/mo, 1 concurrent	10,000/mo, 3 concurrent
Servers	1 instance, 512 MB, sleeps after 15 min idle	3 always-on, 2 GB
Bandwidth	150 GB/mo	2 TB/mo

Compare every plan

Related guides

Deploy a Fastify appFastify servers started from your start script.
Deploy a Node.js appAny Node.js server with a start script: bots, WebSocket servers, workers with an HTTP port.
Deploy a NestJS appNestJS APIs compiled with nest build and started from dist/main.js.

Ship your Express project tonight

Connect the repository and the build settings fill themselves in. Free plan, no card.

Start free