Read and write data to MongoDB using Mongoose and Bun

MongoDB and Mongoose work out of the box with Bun. This guide assumes you've already installed MongoDB and are running it as background process/service on your development machine. Follow this guide for details.

Once MongoDB is running, create a directory and initialize it with bun init.

mkdir mongoose-app
cd mongoose-app
bun init

Then add Mongoose as a dependency.

bun add mongoose

In schema.ts we'll declare and export a simple Animal model.

import * as mongoose from 'mongoose';

const animalSchema = new mongoose.Schema(
    name: {type: String, required: true},
    sound: {type: String, required: true},
    methods: {
      speak() {

export type Animal = mongoose.InferSchemaType<typeof animalSchema>;
export const Animal = mongoose.model('Animal', animalSchema);

Now from index.ts we can import Animal, connect to MongoDB, and add some data to our database.

import * as mongoose from 'mongoose';
import {Animal} from './schema';

// connect to database
await mongoose.connect('mongodb://');

// create new Animal
const cow = new Animal({
  name: 'Cow',
  sound: 'Moo',
await cow.save(); // saves to the database

// read all Animals
const animals = await Animal.find();
animals[0].speak(); // logs "Moo!"

// disconnect
await mongoose.disconnect();

Let's run this with bun run.

bun run index.ts

This is a simple introduction to using Mongoose with TypeScript and Bun. As you build your application, refer to the official MongoDB and Mongoose sites for complete documentation.