This is an overview of the available tools and suggested practices for using Ruby with MongoDB. To skip to more detailed discussion see:

For a list of external resources, see Ruby扩展资源.

Ruby Driver


Install the bson_ext gem for any performance-critical applications.

The MongoDB Ruby driver is the 10gen-supported driver for MongoDB. It’s written in pure Ruby, with a recommended C extension for speed. The driver is optimized for simplicity. It can be used on its own, but it also serves as the basis of several object mapping libraries, such as MongoMapper.


Install / Upgrade

The Ruby driver is hosted at Before installing the driver, make sure you’re using the latest version of rubygems:

gem update --system

Then install the gems:

gem install mongo

To stay on the bleeding edge, you can use the latest source from GitHub. Using your Gemfile:

gem 'mongo', :git => 'git://'

Or Manually:

git clone git://
cd mongo-ruby-driver/
gem build bson.gemspec; gem install bson-x.x.x.gem
gem build bson_ext.gemspec; gem install bson_ext-x.x.x.gem
gem build mongo.gemspec; gem install mongo-x.x.x.gem


In versions of the Ruby driver prior to 0.20, the code for serializing to BSON existed in the mongo gem. Now, all BSON serialization is handled by the required bson gem.

gem install bson

For significantly improved performance, install the bson_ext gem. Using compiled C instead of Ruby, this gem speeds up BSON serialization greatly.

gem install bson_ext

If you are running on Windows, you need the Ruby DevKit installed in order to compile the C extensions.

As long it is in Ruby’s load path, bson_ext will be loaded automatically when you require bson.


Beginning with version 0.20, the mongo_ext gem is no longer used.

To learn more about the Ruby driver, see the Ruby Tutorial and Ruby Documentation.

Object Mappers

Because MongoDB is so easy to use, the basic Ruby driver can be the best solution for many applications.

But if you need validations, associations, and other high-level data modeling functions then an Object Document Mapper may be needed.

In the context of a Rails application these provide functionality equivalent to, but distinct from, ActiveRecord. Because MongoDB is a document-based database, these mappers are called Object Document Mappers (ODM) as opposed to Object Relational Mappers (ORM).

Several mappers are available:

All the mappers build on top of the basic Ruby driver and so some knowledge of that is useful, especially if you work with a custom MongoDB configuration.

Notable Projects

Tools for working with MongoDB in Ruby are being developed daily. See Ruby扩展资源.

If you are working on a project that you would like to have included, let us know.