Get Started

This guide walks through defining non-secret values in layeron.config.ts, choosing the active Layeron environment, and reading values from route code.

1. Define Env Values

Put Env values in layeron.config.ts:

import { project } from "@layeron/core"

export default project({
  app: "./src/app.ts",
  env: {
    defaults: {
      API_BASE_URL: "https://api.example.com",
      FEATURE_CHECKOUT: false,
      REGION: "us-east",
    },
    prod: {
      FEATURE_CHECKOUT: true,
      RATE_LIMIT: 100,
    },
    dev: {
      API_BASE_URL: "http://localhost:3000",
      REGION: "local",
    },
  },
})

defaults apply to every environment. The active environment then overrides those values.

2. Select An Environment

Run local development or deploy with the environment you want to resolve.

layer dev --env dev
layer deploy --env prod

For prod, the resolved Env values above are:

{
  API_BASE_URL: "https://api.example.com",
  FEATURE_CHECKOUT: true,
  REGION: "us-east",
  RATE_LIMIT: 100,
}

3. Read Env Values

Read Env values from runtime code:

import { layeronEnv } from "@layeron/runtime"

app.get("/api/config", () => {
  return {
    apiBaseUrl: layeronEnv("API_BASE_URL").string(),
    checkout: layeronEnv().boolean("FEATURE_CHECKOUT"),
    region: layeronEnv().string("REGION"),
    rateLimit: layeronEnv().number("RATE_LIMIT"),
  }
})

env is also exported as a short alias:

import { env } from "@layeron/runtime"

const region = env("REGION").string()

Next Steps

• Runtime values: Review available readers, supported value types, and the Env versus Secrets boundary.
• Secrets: Use Secret references when runtime code needs sensitive values.
• CLI environment variables: Review CLI environment variables that affect local and deploy commands.