MailProvider

Smartly check whether a given email/domain belongs to a free or disposable mail provider.

There are hundreds of lists available in Github repositories or Gists that list various free and disposable email providers. This gem downloads a bunch of these scripts (pre-configured URLs) and parses them to count votes against each domain in the list. We, then, create a Trie structure to efficiently query this data with a given domain or email. For each query, you get back a number specifying how many sources are claiming that the domain is a free or disposable email provider.

This gem was written in a couple of hours, and the intention has been to get this working first for a project I am working on. This gem still needs refactoring to make the code more readable, tests, etc. PRs welcome :)

• IDN/Punycode compatibility
• should be thread-safe - immutable Trie structure.
• really fast! Uses efficient Patricia Trie structure.
• checks all parts of subdomain for checking an entry
• provide your own sources for disposable/free domains list
• 74000+ disposable domains, 9000+ free domains pre-configured
• check email/domain for free or disposable email provider status

Add this line to your application's Gemfile:

gem 'mail_provider'

And then execute:

bundle

Or install it yourself as:

gem install mail_provider

In simple terms, you can do:

# Re-download and update list of domains from sources
lib = MailProvider.new(refresh: true)

# Re-use cached/parsed list from the CSV in data-directory
lib = MailProvider.new(refresh: false)

# check an email for status
lib.check 'example@c.nut.emailfake.nut.cc'
# => {:ascii=>"c.nut.emailfake.nut.cc",
#     :found=>3,
#     :unicode=>"c.nut.emailfake.nut.cc",
#     :domain=>"nut.cc",
#     :tld=>"cc",
#     :match=>:entry,
#     :summarize=>false,
#     :free=>1,
#     :disposable=>3,
#     :score=>-0.0625,
#     :data=>{"c.nut.emailfake.nut.cc"=>{:free=>1, :disposable=>3},
#             "emailfake.nut.cc"=>{:free=>0, :disposable=>6},
#             "nut.cc"=>{:free=>1, :disposable=>10}},

lib.check "финские-вейдерсы-2019.рф"
# => {:ascii=>"xn----2019-iofqgcb4aasj1c8cik0c5k.xn--p1ai",
#     :found=>1,
#     :unicode=>"финские-вейдерсы-2019.рф",
#     :domain=>"финские-вейдерсы-2019.рф",
#     :tld=>"рф",
#     :data=>{"xn----2019-iofqgcb4aasj1c8cik0c5k.xn--p1ai"=>{:free=>0, :disposable=>1}},
#     :match=>:entry,
#     :score=>-0.0625,
#     :free=>0,
#     :disposable=>1}

# check an email for status while summing up scores for each step in domain
lib.check 'c.nut.emailfake.nut.cc', summarize: true
# => {:ascii=>"c.nut.emailfake.nut.cc",
#     :found=>3,
#     :unicode=>"c.nut.emailfake.nut.cc",
#     :domain=>"nut.cc",
#     :tld=>"cc",
#     :match=>:entry,
#     :summarize=>true,
#     :free=>2,
#     :disposable=>19,
#     :score=>-0.9375,
#     :data=>{"c.nut.emailfake.nut.cc"=>{:free=>1, :disposable=>3},
#             "emailfake.nut.cc"=>{:free=>0, :disposable=>6},
#             "nut.cc"=>{:free=>1, :disposable=>10}},

# check a domain for status
lib.check 'gmail.com'
# => {:ascii=>"gmail.com", :summarize=>false, :checked=>1, :found=>true, :unicode=>"gmail.com",
#     :score=>1.0,:free=>8, :disposable=>0, :data=>{"gmail.com"=>{:free=>8, :disposable=>0}}}

lib.check 'nick@codewithsense.com'
# => {:ascii=>"codewithsense.com", :found=>0, :unicode=>"codewithsense.com",
#     :domain=>"codewithsense.com", :tld=>"com", :data=>{}, :match=>nil,
#     :summarize=>false, :score=>nil}

In the above examples, free is the number of sources claiming that the given domain/email is from a free email provider, disposable is the number of sources claiming that the given domain/email is from a disposable email provider.

checked is the number of domain parts checked for this email/domain for entries present with us. For example, for domain subsub.sub.root.co.in, we check the following strings in our records (giving us a total of 3):

• subsub.sub.root.co.in
• sub.root.co.in
• root.co.in

If summarize is true, counts for each domain parts are added starting from root domain.

score is the percent of sources claiming the string to be a free provider minus the percent of sources claiming the string to be a disposable provider. This value is nil if the string is not found in our entries, otherwise a value between -1 and 1.

The above uses pre-configured list of sources. To use your own list of sources, provide a file with one (url) line per source.

We check the lists for inclusion of gmail.com and mailinator.com and other similar domains to decide what kind of emails they list. To improve efficiency, only provide sources that list EITHER free OR disposable emails, and not both.

Afterwards, you can do:

MailProvider.new(sources: "<path-to-file>", refresh: true)

The gem saves the download and parsed list as a CSV in the gem's directory. You can, optionally, provide a directory to save the parsed list in.

MailProvider.new(data_directory: "<path-to-directory>")

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 rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/nikhgupta/mail_provider. 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.

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

Everyone interacting in the MailProvider project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.