Ruby API for MaxMind minFraud Services


This package provides an API for the MaxMind minFraud web services. This includes minFraud Score, Insights, and Factors. It also includes our minFraud Report Transaction API.

The legacy minFraud Standard and Premium services are not supported by this API.


Add this line to your application's Gemfile:

gem 'minfraud'

And then execute:

$ bundle

Or install it yourself as:

$ gem install minfraud

API Documentation

See the API documentation for more details.



An account ID and license key are required to work with the web services. Configure these before making a request:

Minfraud.configure do |c|
  c.  = 12345
  c.license_key = 'your_license_key'
  c.enable_validation = true

Making a minFraud Score, Insights, or Factors Request

To use the minFraud API, create a Minfraud::Assessments object. The constructor takes a hash of symbols corresponding to each component of the minFraud request. You can also set components by their attribute after creating the object.

After populating the object, call the method for the minFraud endpoint you want to use: #score, #insights, or #factors. The returned value is a MinFraud::Response object. You can access the response model through its #body attribute.

An exception will be thrown for critical errors. You should check for warnings related to your inputs after a request.

# Prepare the request.
assessment =
  device: {
    ip_address:      '',
    accept_language: 'en-US,en;q=0.8',
    session_age:     3600.5,
    session_id:      'foo',
    user_agent:      'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36',
  event: {
    transaction_id: 'txn3134133',
    shop_id:        's2123',
    time:           '2012-04-12T23:20:50+00:00',
    type:           :purchase,
  account: {
    user_id:      '3132',
    username_md5: '4f9726678c438914fa04bdb8c1a24088',
  email: {
    address: '[email protected]',
    domain:  '',
  billing: {
    first_name:         'First',
    last_name:          'Last',
    company:            'Company',
    address:            '101 Address Rd.',
    address_2:          'Unit 5',
    city:               'New Haven',
    region:             'CT',
    country:            'US',
    postal:             '06510',
    phone_number:       '123-456-7890',
    phone_country_code: '1',
  shipping: {
    first_name:         'ShipFirst',
    last_name:          'ShipLast',
    company:            'ShipCo',
    address:            '322 Ship Addr. Ln.',
    address_2:          'St. 43',
    city:               'Nowhere',
    region:             'OK',
    country:            'US',
    postal:             '73003',
    phone_number:       '123-456-0000',
    phone_country_code: '1',
    delivery_speed:     :same_day,
  payment: {
    processor:      :stripe,
    was_authorized: false,
    decline_code:   'invalid number',
  credit_card: {
    issuer_id_number:         '411111',
    last_digits:              '7643',
    bank_name:                'Bank of No Hope',
    bank_phone_country_code:  '1',
    bank_phone_number:        '123-456-1234',
    token:                    'abcd',
    avs_result:               'Y',
    cvv_result:               'N',
    was_3d_secure_successful: true,
  order: {
    amount:           323.21,
    currency:         'USD',
    discount_code:    'FIRST',
    is_gift:          true,
    has_gift_message: false,
    affiliate_id:     'af12',
    subaffiliate_id:  'saf42',
    referrer_uri:     '',
  shopping_cart: [
      category: 'pets',
      item_id:  'leash-0231',
      quantity: 2,
      price:    20.43,
      category: 'beauty',
      item_id:  'msc-1232',
      quantity: 1,
      price:    100.00,
  custom_inputs: {
    section:            'news',
    previous_purchases: 19,
    discount:           3.2,
    previous_user:      true,

# To get the Factors response model, use #factors.
factors_model = assessment.factors.body

factors_model.warnings.each { |w| puts w.warning }

p factors_model.subscores.email_address
p factors_model.risk_score

# To get the Insights response model, use #insights.
insights_model = assessment.insights.body

insights_model.warnings.each { |w| puts w.warning }

p insights_model.risk_score

# To get the Score response model, use #score.
score_model = assessment.score.body

score_model.warnings.each { |w| puts w.warning }

p score_model.risk_score

See the API documentation for more details.

Reporting a Transaction to MaxMind

MaxMind encourages the use of this API, as data received through this channel is used to improve the accuracy of their fraud detection algorithms.

To use the Report Transaction API, create a Minfraud::Components::Report::Transaction object. An IP address and a valid tag are required arguments for this API. Additional parameters may be set, as shown below.

If the report is successful, nothing is returned. If the report fails, an exception will be thrown.

# The report_transaction method only makes use of a transaction component:
txn =
  ip_address:     '',
  tag:            :suspected_fraud,
  maxmind_id:     '12345678',
  minfraud_id:    '58fa38d8-4b87-458b-a22b-f00eda1aa20d',
  notes:          'notes go here',
  transaction_id: '1FA254yZ'
reporter = txn)

See the API documentation for more details.

Persistent HTTP Connections

This gem supports persistent HTTP connections, allowing you to avoid the overhead of creating a new HTTP connection for each minFraud request if you plan to perform more than one. You do not need to do anything to enable this functionality.


The gem supplies several distinct exception-types:

  • RequestFormatError - Raised if an unknown key is provided to the Minfraud::Assessments constructor
  • ClientError - Raised if the IP address is absent, reserved, or the JSON body cannot be decoded
  • AuthorizationError - Raised if there are problems with the account ID and/or license key
  • ServerError - Raised if minFraud returns an error or if there is an HTTP error
  • NotEnumValueError - Raised if an attribute value doesn't belong to the predefined set of values

Thread Safety

This gem is safe for use from multiple threads.

Minfraud::Assessments and Minfraud::Report objects must not be shared across threads.

Please note that you must run Minfraud.configure before calling any functionality using multiple threads.


Please report all issues with this code using the GitHub issue tracker.

If you are having an issue with the minFraud service that is not specific to the client API, please see our support page.


This gem works with Ruby 2.5 and above.


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


This API uses Semantic Versioning.

Copyright (c) 2016-2020 kushnir.yb.

Copyright (c) 2020-2022 MaxMind, Inc.

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

Thank You

This gem is the work of the creator and original maintainer kushnir.yb (@kushniryb).