New Relic is a performance management system, developed by New Relic, Inc (http://www.newrelic.com). New Relic provides you with deep information about the performance of your web application as it runs in production. The New Relic Ruby agent is dual-purposed as a either a Gem or plugin, hosted ...

Provides a better error page for Rails and other Rack apps. Includes source code inspection, a live REPL and local/instance variable inspection for all stack frames.

FnordMetric is a Ruby Event-Tracking gem on steroids

help to kill N+1 queries and unused eager loading.

The exceptionally handsome dashboard framework for Rails.

Supporting gem for Rails Panel (Google Chrome extension for Rails development)

Every Rails page has footnotes that gives information about your application and links back to your editor.

Take a peek into your Rails application.

The official appsignal.com gem

Debugging toolbar for Rack applications implemented as middleware

Monitors Ruby apps and reports detailed metrics on performance to Scout.

An experimental metrics client.

Debugging toolbar for Rack applications implemented as middleware. Based on logical-insight and rack-bug.

The friendly gem that instruments everything for you, like I would if I could.

Collect high level application performance metrics and forward them for analysis

Collect statistics about how your application is performing with ease. Export metrics to various monitoring systems.

Gem to make statistics sending from Ruby applications simple and efficient as possible. Currently supports Statsd, and is inspired by the original ruby-statsd gem by Etsy.

Observe your web applications in the wild! == DESCRIPTION

The Rails View Annotator makes it easy to find out which partial generated which output

Automatic tracing and metrics for Ruby applications. Get started at appoptics.com. @AppOptics

Surface slow code paths in your Rails 3 app via Growl / libnotify

Middleware to show instrumentation information in http headers

Metrics measurement for your app on top of ActiveSupport::Notifications

Gem to make statistics sending from Rails applications simple and efficient as possible

This framework lets you build & easily layout dashboards with your own custom widgets. Use it to make a status boards for your ops team, or use it to track signups, conversion rates, or whatever else metrics you'd like to see in one spot. Included with the framework are ready-made widgets for...

Server for handling metrics from metriks

System Metrics is a Rails 3 Engine that provides a clean web interface to the performance metrics instrumented with ActiveSupport::Notifications