/deno-deploy

Databases on Deno Deploy

Overview

Deno Deploy provides built-in database support with automatic environment isolation. You don't need to manage connection strings or worry about mixing production and development data.

Available Database Engines

Key Concept: Timelines

Deno Deploy automatically creates isolated databases for each environment:

• Production: {app-id}-production
• Git branches: {app-id}--{branch-name}
• Preview deployments: {app-id}-preview

This means your preview deployments won't accidentally modify production data.

Database CLI Commands

Use deno deploy database to manage databases from the command line.

List Databases

# List all databases in your organization
deno deploy database list

# Search for databases by name
deno deploy database list my-prefix

Provision a Database

Create a new managed database:

# Provision a new Deno KV database
deno deploy database provision my-database --kind denokv

# Provision a new Prisma PostgreSQL database (requires --region)
deno deploy database provision my-database --kind prisma --region us-east-1

Link an External Database

Link an existing external postgres database by providing a connection string:

deno deploy database link my-database "postgres://user:pass@host:5432/db"

Assign / Detach

Connect or disconnect a database from an app:

# Assign a database to an app
deno deploy database assign my-database --app my-app

# Detach a database from an app
deno deploy database detach my-database --app my-app

Deno Deploy creates separate databases for each timeline automatically.

Query a Database

Run queries directly from the CLI:

deno deploy database query my-database production "SELECT * FROM users LIMIT 10"

The second argument is the timeline name (e.g., production, preview, or a branch name), which can be found in the output of deno deploy database list.

Delete a Database

deno deploy database delete my-database

Connecting in Code

Deno KV

No configuration needed - just call Deno.openKv():

const kv = await Deno.openKv();

// Deno Deploy automatically connects to the right database
// based on your current environment (production, preview, etc.)

PostgreSQL

Deno Deploy injects standard environment variables that most PostgreSQL libraries detect automatically:

• DATABASE_URL - Full connection string
• PGHOST, PGPORT, PGDATABASE, PGUSER, PGPASSWORD - Individual components

// Recommended: npm:pg (best PostgreSQL driver for Deno Deploy)
import pg from "npm:pg";
const pool = new pg.Pool(); // Reads DATABASE_URL from environment automatically
const { rows } = await pool.query("SELECT * FROM users");

Local Development

With Tunnel

Use --tunnel to connect your local dev server to your hosted development database:

deno task --tunnel dev

This gives you access to the same database environment variables locally.

Without Tunnel

• Deno KV: Data stays in memory during local development
• PostgreSQL: Point to a local PostgreSQL instance or use the tunnel

Migrations

Deno Deploy supports pre-deploy commands that run before each deployment. Use these for database migrations:

{
  "deploy": {
    "preDeploy": ["deno task db:migrate"]
  }
}

Sharing Databases

Multiple apps can share the same database instance. Each app gets its own isolated databases per timeline, even when sharing.

Documentation

• Databases overview: https://docs.deno.com/deploy/reference/databases/
• Deno KV reference: https://docs.deno.com/deploy/reference/deno_kv/