Affirm Ruby API

Run Tests Gem Version

Clean, fast and pure Ruby implementation for the Affirm API

This is using the new Transaction API and is not compatible with the Charge API. Also see the Affirm Changelog


Add this line to your application's Gemfile:

gem 'affirm-ruby-api'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install affirm-ruby-api



If you use this extension and like to support this work, please consider being a sponsor.


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to

Testing support

When implementing this gem into your application or other gem, you can reuse the JSON and HTTP payloads and responses. For example with RSpec you can add the following to your spec_helper.rb file:

require "affirm/testing_support/http_responses"

RSpec.configure do |config|
  config.include Affirm::TestingSupport::HttpResponses

this will provide you with the read_http_fixture and read_json_fixture methods. These can be used to mock the responses and payload body's with WebMock.

For details on how to use this, take a look at the usage in the spec files here.


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Affirm::Ruby::Api project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.