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Ngrok-wrapper gem is a ruby wrapper for ngrok2
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Ngrok-wrapper gem is a ruby wrapper for ngrok v2.

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Ngrok-wrapper is renamed from my fork of the initial awesome Ngrok-tunnel gem by Anton Bogdanovich

I was dealing with debugging work on some webhooks at my current project. Using Ngrok on a free plan, I quickly got tired of Ngrok generating a new endpoint URL every time on restarting the process.

There was a pull request Add support for leaving an ngrok process open and reusing an existing ngrok process instead of starting a new one on every process, but it wasn't quite working.

So, I have created a working one, but neither of these PRs got any reaction from the author.

So, excuse me, Anton Bogdanovich, but I've decided to craft another gem, based on your awesome work, thank you!


Note: You must have ngrok v2+ installed available in your PATH.

Add this line to your application's Gemfile:

gem 'ngrok-wrapper'

And then execute:

$ bundle

Or install it yourself as:

$ gem install ngrok-wrapper


require 'ngrok/wrapper'

# spawn ngrok (default port 3001)

# ngrok local_port
=> 3001

# ngrok external url
=> "http://aaa0e65.ngrok.io"

=> "https://aaa0e65.ngrok.io"

=> true

=> false

# ngrok process id
=> 27384

# ngrok log file descriptor
=> #<File:/tmp/ngrok20141022-27376-cmmiq4>

# kill ngrok
=> :stopped
# ngrok custom parameters
Ngrok::Wrapper.start(addr: 'foo.dev:80',
                    subdomain: 'MY_SUBDOMAIN',
                    hostname: 'MY_HOSTNAME',
                    authtoken: 'MY_TOKEN',
                    inspect: false,
                    log: 'ngrok.log',
                    config: '~/.ngrok2/ngrok.yml',
                    persistence: true,
                    persistence_file: '/Users/user/.ngrok2/ngrok-process.json') # optional parameter
  • If persistence: true is specified, on the 1st server start, an Ngrok process will get invoked, and the attributes of this Ngrok process, like pid, URLs and port will be stored in the persistence_file.
  • On server stop, the Ngrok process will not be killed.
  • On the subsequent server start, Ngrok::Wrapper will read the process attributes from the persistence_file and will try to re-use the running Ngrok process, if it hadn't been killed.
    • The persistence_file parameter is optional when invoking Ngrok::Wrapper.start, by default the '/Users/user/.ngrok2/ngrok-process.json' will be created and used
    • The authtoken parameter is also optional, as long as the config parameter is specified (usually Ngrok config is the ~/.ngrok2/ngrok.yml file)

With Rails

  • Use ~/.ngrok2/ngrok.yml as a config file
  • Set NGROK_INSPECT=false if you want to disable the inspector web-server
  • Add this code at the end of config/application.rb in a Rails project
NGROK_ENABLED = Rails.env.development? &&
                  (Rails.const_defined?(:Server) || ($PROGRAM_NAME.include?('puma') && Puma.const_defined?(:Server))) &&
                  ENV['NGROK_TUNNEL'] == 'true'
  • Add the following code at the start of config/environments/development.rb
  require 'ngrok/wrapper'

  options = { addr: 'https://localhost:3000', persistence: true }
  options[:config] = ENV.fetch('NGROK_CONFIG', "#{ENV['HOME']}/.ngrok2/ngrok.yml")
  options[:inspect] = ENV['NGROK_INSPECT'] if ENV['NGROK_INSPECT']

  puts "[NGROK] tunneling at #{Ngrok::Wrapper.start(options)}"
  puts '[NGROK] inspector web interface listening at' if ENV['NGROK_INSPECT'] == 'true'

  NGROK_URL = Ngrok::Wrapper.ngrok_url_https
  • If you need SSL (https) webhooks, you can use the localhost gem and then, in config/puma.rb:
if self.class.const_defined?(:NGROK_ENABLED)
  bind 'ssl://localhost:3000'
  port ENV.fetch('PORT', 3000)
  • And in config/environments/development.rb:
config.force_ssl = true if NGROK_ENABLED

config.action_mailer.default_url_options = {
  host: NGROK_ENABLED ? NGROK_URL.delete_prefix('https://') : 'myapp.local',
  port: 3000
  • To make the sessions bound to the Ngrok domain, in config/initializers/session_store.rb:
Rails.application.config.session_store :cookie_store,
  key: "_#{Rails.env}_my_app_secure_session_3",
  domain: NGROK_ENABLED ? NGROK_URL.delete_prefix('https://') : :all,
  tld_length: 2
  • To use the webhooks when sending to, for example, Slack API, you can define the redirect URL in controller as follows:
redirect_uri = NGROK_ENABLED ? "#{NGROK_URL}/slack/oauth/#{organization.id}" : slack_oauth_url(organization.id)

With Rack server

  • Use ~/.ngrok2/ngrok.yml as a config file.
  • Set NGROK_INSPECT=false if you want to disable the inspector web-server.
  • Add the following code to the end of a configuration file of your preferred web-server, e.g. config/puma.rb, config/unicorn.rb, or config/thin.rb
require 'ngrok/wrapper'

options = { addr: 'https://localhost:3000', persistence: true }
options[:config] = ENV.fetch('NGROK_CONFIG', "#{ENV['HOME']}/.ngrok2/ngrok.yml")
options[:inspect] = ENV['NGROK_INSPECT'] if ENV['NGROK_INSPECT']

puts "[NGROK] tunneling at #{Ngrok::Wrapper.start(options)}"
puts '[NGROK] inspector web interface listening at' if ENV['NGROK_INSPECT'] == 'true'

NGROK_URL = Ngrok::Wrapper.ngrok_url_https

Gem Maintenance

Preparing a release

Merge all the pull requests that should make it into the new release into the main branch, then checkout and pull the branch and run the github_changelog_generator, specifying the new version as a --future-release cli parameter:

git checkout main
git pull

github_changelog_generator -u texpert -p ngrok-wrapper --future-release v0.1.0

Then add the changes to git, commit and push the Preparing the new release commit directly into the main branch:

git add .
git commit -m 'Preparing the new v0.1.0 release'
git push

RubyGems credentials

Ensure you have the RubyGems credentials located in the ~/.gem/credentials file.

Adding a gem owner

gem owner ngrok-wrapper -a branzeanu.aurel@gmail.com

Building a new gem version

Adjust the new gem version number in the lib/ngrok/wrapper/version.rb file. It is used when building the gem by the following command:

gem build ngrok-wrapper.gemspec

Assuming the version was set to 0.1.0, a ngrok-wrapper-0.1.0.gem binary file will be generated at the root of the app (repo).

  • The binary file shouldn't be added into the git tree, it will be pushed into the RubyGems and to the GitHub releases

Pushing a new gem release to RubyGems

gem push ngrok-wrapper-0.1.0.gem # don't forget to specify the correct version number

Crafting the new release on GitHub

On the Releases page push the Draft a new release button.

The new release editing page opens, on which the following actions could be taken:

  • Choose the repo branch (default is main)
  • Insert a tag version (usually, the tag should correspond to the gem's new version, v0.1.0, for example)
    • the tag will be created by GitHub on the last commit into the chosen branch
  • Fill the release Title and Description
  • Attach the binary file with the generated gem version
  • If the release is not yet ready for production, mark the This is a pre-release checkbox
  • Press either the Publish release, or the Save draft button if you want to publish it later
    • After publishing the release, the the binary gem file will be available on GitHub and could be removed locally


  1. Fork it ( https://github.com/texpert/ngrok-wrapper/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request