{"id":40467,"date":"2025-11-28T11:12:08","date_gmt":"2025-11-28T11:12:08","guid":{"rendered":"https:\/\/www.railscarma.com\/?p=40467"},"modified":"2025-11-28T11:12:11","modified_gmt":"2025-11-28T11:12:11","slug":"setting-up-rails-8-with-mongodb-and-mongoid-guide","status":"publish","type":"post","link":"https:\/\/www.railscarma.com\/sv\/blogg\/setting-up-rails-8-with-mongodb-and-mongoid-guide\/","title":{"rendered":"Setting Up Rails 8 with MongoDB and Mongoid: Guide for 2026"},"content":{"rendered":"
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As Ruby on Rails continues to evolve, the release of <\/span>Rails 8<\/b> has brought modern performance improvements, a cleaner asset pipeline, and better support for API-driven applications. While Rails has traditionally been paired with relational databases such as PostgreSQL or MySQL, many modern applications\u2014especially those requiring flexible schemas, high scalability, or document-based storage\u2014benefit from using <\/span>MongoDB<\/b>, the world\u2019s most popular NoSQL database.<\/span><\/p>

To integrate MongoDB seamlessly with a Rails application, developers use <\/span>Mongoid<\/b>, a mature and fully-featured Object-Document Mapper (ODM). Mongoid replaces ActiveRecord, allowing Rails apps to work smoothly with MongoDB collections and documents instead of relational tables and rows.<\/span><\/p>

In this comprehensive guide, we will walk through <\/span>how to set up Rails 8 with MongoDB and Mongoid<\/b>, step by step. You\u2019ll learn the installation process, project setup, configuration, model creation, routing, and testing\u2014all without touching SQL or migrations. This makes Rails 8 + MongoDB a powerful combination for modern startups, microservices, content-driven applications, and real-time APIs.<\/span><\/p>

Why Choose MongoDB for Rails 8?<\/b><\/h3>

Before diving into the installation steps, it’s important to understand why developers choose MongoDB for certain types of Rails applications.<\/span><\/p>

1. Flexible Schema<\/b><\/h4>

MongoDB stores data as JSON-like documents, allowing you to evolve schemas without rigid migrations.<\/span><\/p>

2. High Scalability<\/b><\/h4>

MongoDB supports horizontal scaling through sharding, making it suitable for high-traffic applications.<\/span><\/p>

3. Ideal for API-Driven Backends<\/b><\/h4>

When building Rails 8 APIs that return JSON, MongoDB\u2019s BSON format maps naturally to Ruby hashes.<\/span><\/p>

4. Faster Development Cycles<\/b><\/h4>

No migrations, instant data structure changes, and easy embedding of nested objects accelerate development.<\/span><\/p>

5. Great Fit for Microservices<\/b><\/h4>

If you’re using Rails in a microservice architecture, MongoDB provides lightweight and independent storage per service.<\/span><\/p>

Mongoid enables Rails developers to enjoy these advantages without changing the familiar MVC structure.<\/span><\/p>

Step 1: Install MongoDB<\/b><\/h3>

To begin integrating MongoDB with Rails 8, you need a running MongoDB server.<\/span><\/p>

macOS (using Homebrew)<\/b><\/p>

brew tap mongodb\/brew
\n<\/code><\/span>brew install mongodb-community
\n<\/code><\/span><\/code><\/span>brew services start mongodb-community<\/code><\/span><\/p>

Ubuntu \/ Debian<\/b><\/p>

sudo apt update<\/code>
<\/span>sudo apt install -y mongodb-org<\/code>
<\/span>sudo systemctl enable --now mongod<\/code><\/span><\/p>

Windows<\/b><\/p>

Download and install the MongoDB Community Server from the official website.<\/span><\/p>

Step 2: Create a New Rails 8 Project Without ActiveRecord<\/b><\/h3>

Rails 8 uses ActiveRecord by default, but MongoDB does not use SQL tables or migrations. So, when generating the Rails app, skip ActiveRecord entirely:<\/span><\/p>

rails new myapp --skip-active-record
\n<\/code><\/span>cd myapp
\n<\/code><\/span><\/p>

This avoids unnecessary SQL database files and configurations.<\/span><\/p>

<\/code><\/span><\/p>

Step 3: Add Mongoid to Your Rails Application<\/b><\/h3>

Edit your <\/span>Gemfil<\/code><\/span>:
<\/span><\/p>

gem \"mongoid\", \"~> 9.0\"<\/code><\/span><\/p>

Mongoid 9+ is optimized for Rails 7 & 8.<\/span><\/p>

Install gems:<\/span><\/p>

paketinstallation<\/code><\/span><\/p>

Step 4: Generate Mongoid Configuration<\/b><\/h3>

Mongoid provides a generator to create the configuration file:
<\/span>rails g mongoid:config<\/code><\/span><\/p>

This creates:
<\/span>config\/mongoid.yml<\/code><\/span><\/p>

Inside this file, you\u2019ll see a default development configuration pointing to:
<\/span>mongodb:\/\/localhost:27017\/myapp_development<\/code><\/span><\/p>

You can customize the database name or add replica sets, authentication, or SSL later.<\/span><\/p>

Step 5: Configure the MongoDB Connection (Optional but Recommended)<\/b><\/h3>

You can modify the default section of <\/span>mongoid.yml<\/code><\/span>:<\/span><\/p>

utveckling:
\u00a0<\/code><\/span>\u00a0kunder:<\/code>
<\/span>\u00a0 \u00a0 standard:<\/code>
<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0database: myapp_db<\/code>
<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0v\u00e4rdar:<\/code>
<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 - localhost:27017<\/code>
<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0options:<\/code>
<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0server_selection_timeout: 5<\/code><\/span><\/p>

MongoDB automatically creates the database when Rails inserts the first record.<\/span><\/p>

Step 6: Create a Mongoid Model<\/b><\/h3>

Mongoid models look very similar to ActiveRecord but use modules instead of inheriting from ActiveRecord::Base.<\/span><\/p>

Generate a model:<\/span><\/p>

rails g model Article<\/code><\/span><\/p>

Open the model file and modify it:<\/span><\/p>

class Article<\/code>
<\/span>\u00a0 \u00a0 inkluderar Mongoid::Document<\/code><\/span>\u00a0 \u00a0
\u00a0 \u00a0include Mongoid::Timestamps<\/code>
<\/span>\u00a0 \u00a0 field :title, type: String<\/code>
<\/span>\u00a0 \u00a0field :body,\u00a0 type: String <\/code>
<\/span>slutet<\/code><\/span><\/p>

Key Mongoid Features:<\/b><\/p>