# Omniauth-auth0 gem authentication failure strategy in Ruby on Rails

**URL:** <https://community.auth0.com/t/omniauth-auth0-gem-authentication-failure-strategy-in-ruby-on-rails/189867>\
**Category:** Get Help\
**Tags:** login-experience, new-universal-login-experience\
**Created:** [July 29, 2025, 9:29pm UTC](https://community.auth0.com/t/omniauth-auth0-gem-authentication-failure-strategy-in-ruby-on-rails/189867 "2025-07-29T21:29:26Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![river.flow](https://upload.wikimedia.org/wikipedia/commons/thumb/7/7c/User_font_awesome.svg/768px-User_font_awesome.svg.png) [@river.flow](https://community.auth0.com/u/river.flow)\
**Post date:** [July 29, 2025, 9:29pm UTC](https://community.auth0.com/t/omniauth-auth0-gem-authentication-failure-strategy-in-ruby-on-rails/189867/1 "2025-07-29T21:29:26Z")

</div>

I am seeking some clarity on Auth0’s authentication **failure** strategy specifically. I am using the `omniauth-auth0` gem implementation in Ruby on Rails that was recommended in the Quickstart guide. I am using authorization flow with Universal Login.

- Does this implementation of Auth0 use OmniAuth’s defaults for authentication failure? For example, is the `/auth/failure` route always used for authentication errors? Are there scenarios where errors are sent to `/callback` instead?
- Is there an example authentication error response that I can see? The `omniauth-auth0` docs (I’m not allowed to include links) have an example of a successful authentication response but I didn’t see anything about failures. I was able purposely trigger a failure due to a missing client secret and see the response but I wasn’t sure if all authentication failures were structured like that.

These questions also relate to how I set up my tests. For example, the regular OmniAuth documentation (again, can’t link to it) recommends using this to mock failure:

```ruby
OmniAuth.config.mock_auth[:twitter] = :invalid_credentials

```

So, I simply adjusted it in my test helper:

```ruby
# /spec/support/auth0_helpers.rb

  def mock_auth0_failure(message: "Authentication failed")
    OmniAuth.config.test_mode = true
    OmniAuth.config.mock_auth[:auth0] = :invalid_credentials
  end

```

And by default, OmniAuth raises exceptions in development and test environments rather than redirecting, so I’m overriding this behavior to make sure my controller action is hit:

```ruby
# /config/initializers/auth0.rb

if Rails.env.development? || Rails.env.test?
  OmniAuth.config.on_failure = Proc.new do |env|
    OmniAuth::FailureEndpoint.new(env).redirect_to_failure
  end
end

```

However, I want to make sure my test assumptions are correct, otherwise they are not very useful. I tried searching the Auth0 docs (for example, the pre-deployment checks) but couldn’t find information specific to failures in OmniAuth with Universal Login. If there’s documentation I simply missed, please feel free to direct me that way.

---

<div class="post-metadata">

**Author:** ![Tiffani](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/tiffani/32/75235_2.png) [@Tiffani](https://community.auth0.com/u/Tiffani)\
**Post date:** [July 30, 2025, 11:57pm UTC](https://community.auth0.com/t/omniauth-auth0-gem-authentication-failure-strategy-in-ruby-on-rails/189867/3 "2025-07-30T23:57:59Z")

</div>

@river.flow glad you’re here. I see it’s your first post in the Auth0 Community, so I just want to confirm that one of our certified Auth0 Community experts will chime in to assist you from here. Hang tight!