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Remove Gem Version Specifiers

Published: Sep 29th, 2020

This is part of Joyful Rails, a list of recommendations to make developing your Rails app more productive and joyful.

In this article, we are talking about removing gem version specifiers.


I recommend removing the gem version specifiers the first time you open the Gemfile, i.e. at your earliest convenience.

I strongly recommend removing the gem version specifiers as soon as you believe your project will be long-lived.


Gem version specifiers place restrictions on what versions of libraries (gems) your app can use. They are useful for preventing gems from being changed to a version that is incompatible with your app.

However, they also prevent you from updating gems on a regular and ongoing basis. As a result, the gems in question will often not be updated until there is a sudden need, for example a severe security vulnerability. And the longer a gem has gone without update, the more difficult the update is likely to be.

You do not want to be stuck doing something very urgent and very difficult some day.

You don’t need gem version specifiers.

Bundler uses a lock file to make sure that your gem versions don’t change until you want them to. Your RSpec tests will make sure that your code works perfectly with the updated gems when you do update them.

Remove the version specifiers from your gem file.


Gem version specifiers show up as arguments to gem in your Gemfile.

For example in the line gem 'puma', '~> 3.11', the version specifier is '~> 3.11'.

Remove these from your Gemfile.

Then run bundle update to upgrade to the latest version of all of your gems.

Make sure you run all of your tests so you know your application runs correctly with your new gem versions.