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CI NPM version js-standard-style

Fastify MongoDB connection plugin; with this you can share the same MongoDB connection pool in every part of your server.

Under the hood the official MongoDB driver is used, the options that you pass to register will be passed to the Mongo client. The mongodb driver is v6.x.x.

If you do not provide the client by yourself (see below), the URL option is required.


npm i @fastify/mongodb


Add it to your project with register and you are done!

const fastify = require('fastify')()

fastify.register(require('@fastify/mongodb'), {
  // force to close the mongodb connection when app stopped
  // the default value is false
  forceClose: true,
  url: 'mongodb://mongo/mydb'

fastify.get('/user/:id', async function (req, reply) {
  // Or this.mongo.client.db('mydb').collection('users')
  const users = this.mongo.db.collection('users')

  // if the id is an ObjectId format, you need to create a new ObjectId
  const id = new this.mongo.ObjectId(
  try {
    const user = await users.findOne({ id })
    return user
  } catch (err) {
    return err

fastify.listen({ port: 3000 }, err => {
  if (err) throw err

You may also supply a pre-configured instance of mongodb.MongoClient:

const mongodb = require('mongodb')
  .then((client) => {
    const fastify = require('fastify')()

    fastify.register(require('@fastify/mongodb'), { client: client })
      .register(function (fastify, opts, next) {
        const db = fastify.mongo.client.db('mydb')
        // ...
        // ...
        // ...
  .catch((err) => {
    throw err


  • the passed client connection will not be closed when the Fastify server shuts down.
  • in order to terminate the MongoDB connection you have to manually call the fastify.close method (for example for testing purposes, otherwise the test will hang).
  • mongodb connection timeout is reduce from 30s (default) to 7.5s in order throw error before fastify plugin timeout.


This plugin decorates the fastify instance with a mongo object. That object has the following properties:

The ObjectId class can also be directly imported from the plugin as it gets re-exported from mongodb:

const { ObjectId } = require('@fastify/mongodb')

const id = new ObjectId('some-id-here')

The db property is added only if:

  • a database string option is given during the plugin registration.
  • the connection string contains the database name. See the Connection String URI Format

A name option can be used in order to connect to multiple MongoDB clusters.

const fastify = require('fastify')()

  .register(require('@fastify/mongodb'), { url: 'mongodb://mongo1/mydb', name: 'MONGO1' })
  .register(require('@fastify/mongodb'), { url: 'mongodb://mongo2/otherdb', name: 'MONGO2' })

fastify.get('/', function (req, res) {
  // This collection comes from "mongodb://mongo1/mydb"
  const coll1 = this.mongo.MONGO1.db.collection('my_collection')
  // This collection comes from "mongodb://mongo2/otherdb"
  const coll2 = this.mongo.MONGO2.db.collection('my_collection')
  // ...
  // ...
  // do your stuff here
  // ...
  // ...


This project is kindly sponsored by:


Licensed under MIT.