Runtimes

Choose packages by runtime boundary

jsorm separates authoring APIs, runtime-safe imports, CLI ownership, and database transport so each environment gets only what it can safely run.

Package selection at a glance

Package	Use it for	Do not use it for
@jsorm/core	Main authoring package for models, queries, config types, and migration primitives in Node-capable apps	Edge bundles that cannot use Node APIs or native binaries
@jsorm/runtime	Universal or edge-safe application code, plus direct config injection when filesystem access is unavailable	Owning the jsorm CLI
@jsorm/node	Tooling and runtime package for Node and Bun. On Node it provides the Rust engine bridge and native adapter plumbing for migrations and deploy workflows. On Bun it detects Bun config and uses Bun native DB APIs directly (no Rust engine)	CLI ownership or edge request handlers
@jsorm/fetch	HTTP/fetch database transport for runtimes without TCP sockets or native binaries	Migration ownership or jsorm deploy
@jsorm/pg, @jsorm/mysql, @jsorm/sqlite	Native adapters for direct database access from Node	Edge runtimes without raw TCP access

Recommended combinations

• Node app runtime: @jsorm/core or @jsorm/node with a native adapter package
• Bun runtime: @jsorm/node — detects Bun and uses Bun native database APIs directly, no Rust engine
• Edge runtime: @jsorm/runtime with @jsorm/fetch
• CI, release, and deploy jobs: @jsorm/core + @jsorm/node in a Node 24+ environment

Caution

@jsorm/fetch is runtime-safe transport for queries, not a migration adapter. Keep jsorm deploy and other migration workflows in a separate Node environment.

Environment guide

Node services and workers

Use native adapters when your runtime can open direct database connections and run Node APIs.

pnpm add @jsorm/core @jsorm/node @jsorm/pg pg

import { createJsorm, defineConnectionSource, defineJsormConfig } from '@jsorm/core';
import { pgAdapter } from '@jsorm/pg';

const main = defineConnectionSource({
  adapter: pgAdapter({
    name: 'main',
    connectionString: process.env.DATABASE_URL!,
  }),
});

const config = defineJsormConfig({
  connectionSources: { main },
  defaults: { connectionSource: 'main' },
});

export const db = await createJsorm().init(config);

Use this shape for long-lived servers, background workers, and containerized Node apps.

Bun services and scripts

Use @jsorm/node on Bun. The package detects the Bun runtime and uses Bun’s built-in SQLite, MySQL-compatible, and PostgreSQL-compatible APIs directly — bypassing the Rust engine entirely.

pnpm add @jsorm/core @jsorm/node @jsorm/pg pg

import { createJsorm, defineConnectionSource, defineJsormConfig } from '@jsorm/core';
import { pgAdapter } from '@jsorm/pg';

const main = defineConnectionSource({
  adapter: pgAdapter({
    name: 'main',
    connectionString: process.env.DATABASE_URL!,
  }),
});

const config = defineJsormConfig({
  connectionSources: { main },
  defaults: { connectionSource: 'main' },
});

export const db = await createJsorm().init(config);

On Bun, adapter calls go through Bun’s native database bindings instead of the Rust worker. The query API, type inference, and config shape are identical to Node.

Edge and fetch-only runtimes

Use runtime-safe imports plus @jsorm/fetch when the request runtime cannot use raw TCP sockets or native binaries.

pnpm add @jsorm/runtime @jsorm/fetch
pnpm add -D @jsorm/node

import { createJsorm, defineConnectionSource, defineJsormConfig } from '@jsorm/runtime';
import { fetchAdapter } from '@jsorm/fetch';

const main = defineConnectionSource({
  adapter: fetchAdapter({
    name: 'main',
    dialect: 'postgres',
    endpoint: process.env.SQL_HTTP_ENDPOINT!,
    headers: () => ({
      authorization: `Bearer ${process.env.SQL_HTTP_TOKEN!}`,
    }),
  }),
});

const config = defineJsormConfig({
  connectionSources: { main },
  defaults: { connectionSource: 'main' },
});

export const db = await createJsorm().init(config);

This is the recommended path for Vercel Edge, Cloudflare Workers, and other fetch-only runtimes.

CI and deploy workflows

Run migration and deploy commands from Node, even if the application itself runs at the edge.

pnpm exec jsorm deploy --strict --verbose

Typical places to run this:

• GitHub Actions
• a release container or init job
• a dedicated Node deployment step before rollout

Quick decision matrix

Environment	Runtime package	Transport	Migration/deploy owner
Node API/server	@jsorm/core or @jsorm/node	native adapter	same Node runtime or CI job
Bun service / script	@jsorm/node	Bun native API	same Bun runtime or CI job (Node)
Vercel Edge / Workers	@jsorm/runtime	@jsorm/fetch	separate @jsorm/core + @jsorm/node job
CI / release pipeline	@jsorm/core + @jsorm/node	native adapter	@jsorm/core + @jsorm/node

Engine mode and workers

jsorm uses a persistent worker process by default in Node runtimes to eliminate per-query spawn overhead. When engine.mode is omitted in jsorm.config.ts, it defaults to "worker".

// jsorm.config.ts
export default defineJsormConfig({
  engine: {
    // mode defaults to "worker"
    worker: {
      startupTimeoutMs: 5_000,
      requestTimeoutMs: 10_000,
      restartLimit: 3,
    },
  },
});

You can fall back to legacy per-query execution by explicitly setting engine.mode: "spawn" if needed. Note that worker mode is Node.js runtime only — on Bun, @jsorm/node bypasses the Rust engine entirely and uses Bun’s native database APIs.

Shared resources and isolation

Runtimes in the same Node process share adapter pools and Rust worker processes when their effective configuration fingerprint matches.

• createJsorm(): Standard instances automatically participate in the shared-resource registry. This avoids recreating DB connection pools across repeated imports.
• createJsormTest(): Sandboxed instances for testing intentionally disable filesystem config discovery and isolate their resources by default, preventing tests from trampling on each other’s pools.

import { createJsorm, createJsormTest } from '@jsorm/core';

// Reuses shared worker and connection pools based on config fingerprint
const appDb = await createJsorm().init();

// Uses isolated resources by default
const testDb = await createJsormTest().init();

Native adapters

Choose the adapter package that matches your database:

• PostgreSQL → @jsorm/pg
• MySQL / PlanetScale → @jsorm/mysql
• SQLite → @jsorm/sqlite

Install only the adapter packages you actually use. The core packages do not bundle database drivers by default.

Best practices

1. Keep app/runtime imports and CLI ownership separated.
2. Use native adapters in Node, and @jsorm/fetch only for fetch-only runtimes.
3. On Bun, @jsorm/node detects the runtime automatically — the same package works for both Node and Bun.
4. Run jsorm deploy outside edge functions.
5. Treat CI and release jobs as Node environments with full migration responsibility.