Backend entry

The backend entry default-exports a backend(...) app.

import { backend } from "@layeron/core"

const app = backend({
  project: "billing",
  compatibilityDate: "2026-05-24",
})

export default app

backend(options)

Create a Layeron backend app.

backend(options: BackendOptions): BackendApp

backend(...) parameters

Options accepted by backend().

Field	Type	Required	Description
project	string	yes	Stable project slug used for compilation, deployment state, and resource naming.
name	string | undefined	no	Human-readable app display name.
endpoint	string | undefined	no	App endpoint metadata recorded with the app spec.
gateway	Layeron.Runtime.Gateway.GatewayConfig | undefined	no	Public Gateway runtime configuration.
compatibilityDate	string | undefined	no	Cloudflare Workers compatibility date.
compatibilityFlags	string[] | undefined	no	Cloudflare Workers compatibility flags.
observability	Layeron.Observability.ObservabilityConfig | undefined	no	App-level observability policy.
placement	Layeron.Common.Placement.LayeronPlacement | undefined	no	App-level placement defaults for compute, data resources, and Durable Objects.

Common fields

• project: stable project slug used for compilation and naming.
• gateway: public ingress policy, CORS, request ids, traces, and Gateway logs.
• compatibilityDate: Workers runtime compatibility version.
• compatibilityFlags: extra Workers runtime flags.
• observability: app-level logging, events, and trace policy.
• placement: app-level placement defaults for Workers compute, data resources, and Durable Objects.

Placement

Use placement on backend(...) to set app-wide defaults. Use placement on an individual product to override one product instance.

import { backend } from "@layeron/core"
import { db, realtime, storage } from "@layeron/modules"

const app = backend({
  project: "media",
  placement: {
    compute: {
      mode: "smart",
      locationHint: "weur",
    },
    data: {
      locationHint: "weur",
    },
    durableObjects: {
      locationHint: "weur",
    },
  },
})

const database = db({
  name: "main",
  placement: {
    data: {
      locationHint: "enam",
    },
  },
})

const files = storage.bucket({ name: "uploads" })
const rooms = realtime({ name: "rooms" })

app.use(database)
app.use(files)
app.use(rooms)

export default app

Product placement merges with backend placement by field. data applies to D1 and R2 resources. compute applies to Workers. durableObjects applies to Durable Object namespaces and runtime stub selection.

Data placement accepts wnam, enam, weur, eeur, apac, and oc. Compute and Durable Object placement also accept sam, afr, and me. jurisdiction accepts eu and fedramp for data and Durable Object placement.