envsafe

Tiny, dependency-free utility that fails fast if required environment variables are missing or invalid.

Install

npm i envsafe

Core usage

import { envsafe } from "envsafe";

envsafe(["DATABASE_URL", "JWT_SECRET"]);

// Your app starts only if env is valid.

Options

envsafe(["DATABASE_URL"], {
  disallowEmpty: true, // default
  messagePrefix: "[my-app] "
});

Optional typed getters

import { envsafe, envString, envNumber, envBoolean } from "envsafe";

envsafe(["DATABASE_URL"]);

const port = envNumber("PORT", { default: 3000 });
const isProd = envBoolean("NODE_ENV", { default: false, truthy: ["production"] });
const databaseUrl = envString("DATABASE_URL");

Notes

• Zero runtime dependencies
• Works with Node, Express, Next.js, serverless, etc.
• Designed to run at startup (top-level import / early initialization)