DomainRuntimedocs
Introduction
PlannedWhat works todayReviewed 2026-09-22

Project structure

The files a DomainRuntime app has and what each one is for.

Planned layout. create-app today also generates src/runtime.ts, instant.schema.ts and an /api/domain route for the standalone adapter; druntime does not need them.
my-app/
├─ src/
│  ├─ domain.ts              your domain: entities, links, actions
│  ├─ lib/db.ts              the browser client, typed from the domain
│  └─ app/                   your Next.js app
├─ .domainruntime/
│  ├─ dev.json               what druntime runs: domain entry and client commands
│  ├─ link.json              the project and environment this folder is linked to (druntime link)
│  └─ dev-session.json       the running development session (not in git)
├─ .env.local                DOMAIN_RUNTIME_URL and public configuration, written by druntime (not in git)
├─ DOMAIN.md                 your business in plain words, for people and agents
└─ package.json

src/domain.ts

The source of truth. The database schema, the typed client and the action endpoints are derived from it. Keep it free of UI code: it runs in the runtime, not in the browser.

For a larger product, split it and compose:

src/domain/
├─ index.ts        export default the root domain
├─ orders.ts       domain("orders").withSchema({…}).withActions({…})
└─ billing.ts      domain("billing").includes(orders).withSchema({…}).withActions({…})

.domainruntime/dev.json

{
  "name": "my-app",
  "domain": "src/domain.ts",
  "clients": [
    { "name": "web", "cwd": ".", "command": ["pnpm", "run", "dev"] }
  ]
}

clients lists the commands druntime starts and gives the environment's URL. Add an Expo or desktop app the same way. See Local development.

Naming

  • Domain names are camelCase: orders, supplierNetwork.
  • Entities are prefixed with their domain: orders_order, orders_lineItem. Entities share one namespace per environment and domains are composed, so the prefix keeps them apart and tells a reader which domain owns each one.
  • Action ids are <domain>.<action>: orders.place.

How it works

The mental model: a domain, live reads, actions as the only writes, and what each piece guarantees.

Using LLMs

Give your coding agent the docs and the rules it needs to write DomainRuntime code correctly.

On this page

src/domain.ts.domainruntime/dev.jsonNaming