# Use Knex with Koa and Postgres

Connect a Koa app to a free EasyHost Postgres database using Knex, from install to deployment.

## Create the database

```
npx ezhst db create main
npx ezhst db info --json
npx ezhst env set DATABASE_URL="postgresql://..."
```

The connection string uses a public host with TLS, so it works from your laptop too. Put it in your local `.env` for development.

## Install Knex

```
npm i knex pg
```

## Create the client

```src/db.ts
import knex from "knex";

export const db = knex({
  client: "pg",
  connection: process.env.DATABASE_URL,
  pool: { min: 0, max: 5 },
});
```

Run `knex migrate:latest` from your machine with `DATABASE_URL` pointing at EasyHost. Pool settings count against the limit of 20 connections.

Koa does not bundle your code, so drivers load normally from `node_modules`.

## Query it from a route

```src/index.ts
import { db } from "./db";
router.get("/api/users", async (ctx) => {
  const rows = await db("users").select("id", "email").limit(20);
  ctx.body = rows;
});
```

## Run migrations

Run migrations from your machine, with `DATABASE_URL` set to the EasyHost connection string.

```
npx knex migrate:latest
```

Commit the migration files so every environment applies the same changes.

## Deploy

```
npx ezhst deploy
```

Each database allows 20 concurrent connections, and Koa shares them across requests. See the [Koa hub](/frameworks/koa) for every Koa guide, or [free Koa hosting](/free-koa-hosting) for what is included. See also the [Postgres product page](/products/postgres).

## Frequently asked questions

### Is Postgres free for my Koa app?

Yes. Each EasyHost project can have one Postgres 16 database with no expiry date.

### Can I use Knex locally against the same database?

Yes. The connection string works from outside EasyHost. A separate development database is safer once you have real data.