ActiveRecord Tableless Models provides a simple mixin for creating models that are not bound to the database. This approach is useful for taking advantage of the features of ActiveRecord such as validation, relationships, etc.

acts_as_xlsx lets you turn any ActiveRecord::Base inheriting class into an excel spreadsheet. It can be added to any finder method or scope chain and can use localized column and sheet names with I18n.

Client Side Validations for Rails 2.x and 3.x

A Ruby on Rails plugin to add an after_commit callback. This can be used to trigger methods only after the entire transaction is complete.

A Rails library for storing user sessions in a backend database

Chamber lets you source your Settings from an arbitrary number of YAML files and provides a simple mechanism for overriding settings from the ENV, which is friendly to how Heroku addons work.

A malware/botnet analysis framework written in Ruby.

Stores draft versions of your ActiveRecord models' data in a single table or split up into separate tables. Works with Ruby on Rails and Sinatra.

Quickly get a count estimation for large tables.

FastPage applies the MySQL "deferred join" optimization to your ActiveRecord offset/limit queries.

FortyFacets lets you easily build explorative search interfaces based on fields of your active_record models.

Functional Reactive Programming with EventSourcing in Ruby

Functional Reactive Programming with EventSourcing in Ruby

Preload ActiveRecord associations with graphql-batch

Rails Driver and Adapter for IBM Data Servers: {DB2 on Linux/Unix/Windows, DB2 on zOS, DB2 on i5/OS, Informix (IDS)}

The JitPreloader has the ability to send notifications when N+1 queries occur to help guage how problematic they are for your code base and a way to remove all of the commons explicitly or automatically

With it you can add the ability to create columns outside the default schema, directly in your model in a similar way that you just know in others projects like DataMapper or MongoMapper.

JRuby gem for performing multidimensional queries of relational database data using Mondrian OLAP Java library

An awesome nested set implementation for Active Record

A Postgres advisory lock client