Fastify plugin to check environment variables

Usage no npm install needed!

<script type="module">
  import fastifyEnv from '';



CI NPM version Known Vulnerabilities js-standard-style

Fastify plugin to check environment variables


npm install --save fastify-env


const fastify = require('fastify')()
const fastifyEnv = require('fastify-env')

const schema = {
  type: 'object',
  required: [ 'PORT' ],
  properties: {
    PORT: {
      type: 'string',
      default: 3000

const options = {
  confKey: 'config', // optional, default: 'config'
  schema: schema,
  data: data // optional, default: process.env

  .register(fastifyEnv, options)
  .ready((err) => {
    if (err) console.error(err)

    console.log(fastify.config) // or fastify[options.confKey]
    // output: { PORT: 3000 }

This module is a wrapper around env-schema. To read an .env file you must set dotenv in the options:

const options = {
  dotenv: true // will read .env in root folder

// or, pass config options avalible on dotenv module
const options = {
  dotenv: {
    path: `${__dirname}/.env`,
    debug: true

NB Support for additional properties in the schema is disabled for this plugin, with the additionalProperties flag set to false internally.


In order to have typing for the fastify instance, you should follow the example below:

declare module 'fastify' {
  interface FastifyInstance {
    config: { // this should be same as the confKey in options
      // specify your typing here


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