SQLite

SQLite is the local driver behind db. It keeps your records in a file on your machine, so mainsdk dev runs offline with no database server, cloud account or connection string. Your code calls the same db.<model>.for(user) methods it calls in production. Pick it for local development and quick prototypes; production uses Postgres, Neon or Supabase, and mainsdk check enforces that.

db:
  driver: sqlite

Before you start

Nothing to set up. SQLite is an embedded database that runs inside your app's process, so there is no server, account or key.

1. Install MainSDK and run mainsdk dev. Every interface ships a local driver, and SQLite is the one for db.
2. Pick a production driver early, such as Postgres, so your production overlay is ready before your first deploy.

Configure

Keep SQLite in your development overlay and a real driver in production.

db:
  driver: sqlite

db:
  driver: postgres
  regions: { us: secret:DB_US, eu: secret:DB_EU, in: secret:DB_IN }   # suggested names

Where the SQLite file lives, and how the local driver handles the us, eu and in regions, are not defined yet. Field labels under db.fields apply as they do on any driver.

Use it

import { auth, db } from "mainsdk";

export async function GET(req: Request) {
  const session = await auth.require(req);
  const orders = await db.orders.for(session.user).list({ limit: 20 });
  return Response.json(orders);
}

The same code runs unchanged when production points db at Postgres.

Local development and testing

• mainsdk dev: runs db on SQLite with no provider key or network.
• Tests: createTestApp() from @mainsdk/testing runs db on its in-memory fake, and chaos.on("db", { outage: true }) simulates the store going down.
• Before you ship: run npx mainsdk check --env prod locally or in CI to confirm production no longer resolves to SQLite.

What MainSDK adds on top

• No query without an owner scope, on SQLite as on every driver.
• Personal fields carry a label; a field labelled pan is refused.
• A repeated idempotency key on create or update never writes twice.
• Production can't run on it: mainsdk check fails with MAIN-DATA-0030.

See Data and records for the full contract.

Limits and notes

• Local only. Setting db.driver: sqlite for production fails mainsdk check with MAIN-DATA-0030; set db.driver to postgres, neon or supabase for prod.
• The SQLite driver comes with the db spec (phase 1).
• SQLite is not a regional store, so it does not prove your residency setup; test region routing against your real driver.

Swap to or from it

db:
  driver: postgres   # was sqlite

FAQ

Can I use SQLite in production for a small app? No. The check refuses it with MAIN-DATA-0030, so every production app gets regional stores, backups and drills from a real provider.

Do my Prisma or Drizzle migrations work with it? The db spec pairs the SQLite local driver with Prisma and Drizzle adapters; how migrations run against the local file is not decided yet.

Next

• Data and records
• Postgres and Neon
• Swap a driver

Open questions