@broberg/config

The fleet's single-source config helper — the reusable mechanism behind the "ALDRIG hardcoded values — one source, trickle down" rule. Validate + type your environment once at boot, declare typed business constants in one place, and coerce loose env strings safely. Framework-agnostic (Node · Bun · edge).

zod is a peer dependency (only the schema you pass touches it):

npm i @broberg/config zod

parseEnv(schema, source?)

Validate + type an env object against a Zod schema, failing fast with a readable list of every offending key. Call once at boot, export the result, and never read process.env directly afterwards.

import { z } from "zod";
import { parseEnv } from "@broberg/config";

export const env = parseEnv(
  z.object({
    PORT: z.coerce.number().int().positive().default(3000),
    DATABASE_URL: z.string().min(1),
    RESEND_API_KEY: z.string().min(1, "RESEND_API_KEY is required"),
    MAIL_LIVE: z.enum(["true", "false"]).default("false"),
  }),
);

env.PORT; // number — coerced + validated

A missing/invalid key throws at startup with every problem listed, so the app never boots in a misconfigured state:

Invalid environment configuration:
  - DATABASE_URL: Required
  - PORT: Number must be greater than 0

defineConfig(config)

An identity function that brands a plain object as the single typed source for a set of business constants (fee tiers, shop settings, magic numbers). No runtime behaviour — it just gives you one typed import boundary so values don't drift.

import { defineConfig } from "@broberg/config";

export const FEES = defineConfig({ platformPercent: 5, payoutDelayDays: 7 });

coerceInt(name, fallback, source?) / coerceBool(name, fallback, source?)

The no-Zod escape hatch for the lightweight plain-object pattern. Read one var with a fallback when absent; throw loudly on a present-but-malformed value (a typo'd number/bool should fail, not silently become NaN/false).

import { coerceInt, coerceBool } from "@broberg/config";

const quorum = coerceInt("GF_QUORUM", 3); // throws on "abc" / "1.5"
const live = coerceBool("MAIL_LIVE", false); // true/false/1/0/yes/no/on/off

productionGuard(config, requiredKeys, nodeEnv?)

In production, assert that every required key is truthy — so a missing secret crashes the boot instead of silently shipping a dev default. A no-op elsewhere.

import { productionGuard } from "@broberg/config";

productionGuard(env, ["RESEND_API_KEY", "AUTH_SECRET"]);
// in production with AUTH_SECRET unset:
//   Error: Missing required production config: AUTH_SECRET

Next.js caveat

NEXT_PUBLIC_* vars are inlined by the bundler at build time and are absent from the server runtime's process.env. Do not route them through parseEnv server-side — reference process.env.NEXT_PUBLIC_X directly in client code, and keep parseEnv for true server env (secrets, URLs, flags).

Apps, not libraries

parseEnv's fail-fast belongs in a consuming app's startup — not inside a library or SDK. A library should read keys lazily and stay able to "ship-dark" with partial/absent keys (e.g. @broberg/ai-sdk reads FAL_KEY ?? FAL_API_KEY at call-time and instantiates with stub providers so it works in test/partial-key environments). Wrapping a library's internal env reads in parseEnv would kill that optional-key / ship-dark behaviour. Rule: wrap your app's env at boot; never a dependency's internal reads.

Part of the broberg.ai shared inventory. Search before you build: GET https://discovery.broberg.ai/api/search?q=config.