Databases

Leash provides managed PostgreSQL databases. When you deploy an app that uses a database, the CLI detects it and offers to create one for you.

Automatic Detection

The CLI detects database dependencies in your package.json, requirements.txt, go.mod, and other manifest files. If it finds PostgreSQL packages, it offers to provision a database.

Deploy Flow

When a database dependency is detected during deploy, the CLI gives you three choices:

How It Works

• Each app gets its own isolated PostgreSQL database and user
• DATABASE_URL is automatically injected as an environment variable
• Your ORM (Prisma, SQLAlchemy, etc.) creates tables on first connection
• Daily automated backups with 7-day retention

Instance sizing

Each provisioned database is a small Postgres instance suitable for running one app: low connection count, short query budget, and modest storage. We tune the exact resources to the platform's current defaults rather than publishing a per-plan matrix here; the dashboard shows the live limits for your database after it's created.

Need a bigger instance, dedicated resources, or a different region? Use “Bring your own database” below and point Leash at any external Postgres.

Applying a schema

Keep your schema in source. Two files do the work:

• db/schema.sql — full source of truth for the schema (re-runnable from a clean DB).
• db/migrations/<timestamp>_<name>.sql — append-only, one file per change after the first deploy.

1. Write the initial schema

create table if not exists notes (
  id        uuid primary key default gen_random_uuid(),
  body      text not null,
  user_id   text not null,
  created_at timestamptz not null default now()
);

create index if not exists notes_user_id_idx on notes (user_id);

2. Apply it locally

With leash dev running, your app has DATABASE_URL in its env. Apply the schema directly with psql:

Or use whichever migrator your stack prefers — Prisma (prisma db push / prisma migrate dev), Knex, Alembic, golang-migrate, sqlx-cli. They all read DATABASE_URL.

3. Ship migrations alongside code

For incremental changes after the first deploy, add a new file to db/migrations/:

alter table notes
  add column if not exists color text not null default 'gray';

Apply it with the same migrator. Migrations are append-only — never edit a migration that's been applied to a deployed environment. To revert, create a new migration that undoes the change.

Run migrations as part of your deploy process — most stacks support a release-phase hook (e.g. prisma migrate deploy for Node, alembic upgrade head for Python, migrate up for Go).

Common Issues

Bring Your Own Database

Already using an external database? Choose option [2] during deploy or set the connection string manually.

Set the connection string in your app's Environment tab on the dashboard. Use the appropriate variable name for your database:

Supabase

Set DATABASE_URL to your Supabase connection string.

Neon

Set DATABASE_URL to your Neon connection string.

MongoDB Atlas

Set MONGODB_URI to your Atlas connection string.

Redis (Upstash / Redis Cloud)

Set REDIS_URL to your Redis connection string.