Current version: 4.2.1 | Documentation for: v1.0.4 v2.2.1 v3.7.0

Web Console CI

Web Console is a debugging tool for your Ruby on Rails applications.


Add the following to your Gemfile:

group :development do
  gem 'web-console'


The web console allows you to create an interactive Ruby session in your browser. Those sessions are launched automatically in case of an error and can also be launched manually in any page.

For example, calling console in a view will display a console in the current page in the context of the view binding.

<% console %>

Calling console in a controller will result in a console in the context of the controller action:

class PostsController < ApplicationController
  def new
    @post =

The method is defined in Kernel and you can invoke it any application code.

Only one console invocation per request is allowed. If you happen to have multiple ones, WebConsole::DoubleRenderError will be raised.


Web Console allows you to execute arbitrary code on the server. Therefore, be very careful who you give access to.


By default, only requests coming from IPv4 and IPv6 localhosts are allowed.

config.web_console.permissions lets you control which IP's have access to the console.

You can allow single IP's or whole networks. Say you want to share your console with

class Application < Rails::Application
  config.web_console.permissions = ''

If you want to allow the whole private network:

Rails.application.configure do
  config.web_console.permissions = ''

Take a note that IPv4 and IPv6 localhosts are always allowed. This wasn't the case in 2.0.


When a console cannot be shown for a given IP address or content type, messages such as the following is printed in the server logs:

Cannot render console from! Allowed networks:, ::1

If you don't want to see this message anymore, set this option to false:

Rails.application.configure do
  config.web_console.whiny_requests = false


If you want to style the console yourself, then you can place style.css at a directory pointed by config.web_console.template_paths:

Rails.application.configure do
  config.web_console.template_paths = 'app/views/web_console'

You may want to check the templates folder at the source tree for the files you may override.


Usually the middleware of Web Console is mounted at /__web_console. If there is a need to change the path, then you can specify it by config.web_console.mount_point:

Rails.application.configure do
  config.web_console.mount_point = '/path/to/web_console'


Where did /console go?

The remote terminal emulator was extracted in its own gem which is no longer bundled with Web Console.

If you miss this feature, check out rvt.

Why do I constantly get unavailable session errors?

All of Web Console sessions are stored in memory. If you happen to run on a multi-process server (like Unicorn), you may encounter unavailable session errors while the server is still running. This is because a request may hit a different worker (process) that doesn't have the desired session in memory. To avoid that, if you use such servers in development, configure them so they serve requests only out of one process.


Enable sticky sessions for Passenger on Nginx or Passenger on Apache to prevent unavailable session errors.

How to inspect local and instance variables?

The interactive console executes Ruby code. Invoking instance_variables and local_variables will give you what you want.

Why does the console only appear on error pages but not when I call it?

This can be happening if you are using Rack::Deflater. Be sure that WebConsole::Middleware is used after Rack::Deflater. The easiest way to do this is to insert Rack::Deflater as early as possible

Rails.application.configure do
  config.middleware.insert(0, Rack::Deflater)

Why am I getting an undefined method web_console?

Make sure your configuration lives in config/environments/development.rb.