@std/dotenv

Overview

Parses and stringifies data in the .env file format.

Note: The key needs to match the pattern /^[a-zA-Z_][a-zA-Z0-9_]*$/.

import { parse, stringify } from "@std/dotenv";
import { assertEquals } from "@std/assert";

assertEquals(parse("GREETING=hello world"), { GREETING: "hello world" });
assertEquals(stringify({ GREETING: "hello world" }), "GREETING='hello world'");

Migrating from load()

load, loadSync and the @std/dotenv/load side-effect module are deprecated in favor of the runtime's --env-file flag, which Node.js and Bun also support:

deno run --env-file app.ts
deno run --env-file=.env --env-file=.env.local app.ts

Differences to be aware of:

• load() silently ignores a missing file. --env-file warns but continues, while the parse() replacement above throws. To treat the file as optional:

import { parse } from "@std/dotenv";

let env: Record<string, string> = {};
try {
  env = parse(await Deno.readTextFile(".env"));
} catch (e) {
  if (!(e instanceof Deno.errors.NotFound)) throw e;
}

• $VAR inside a double-quoted value stays literal with load() but expands with --env-file. Use single quotes for values containing a literal $.
• ${KEY:-default} and nested defaults are not supported by --env-file. Use parse, which keeps the full expansion behavior.
• Node's --env-file performs no variable expansion at all.
• On platforms without a CLI, e.g. Deno Deploy, set environment variables through the platform's configuration instead.

Add to your project

deno add jsr:@std/dotenv

See all symbols in @std/dotenv on