EmailDomainChecker

Email address validation and domain checking library to prevent mail server reputation degradation.

Installation

Add this line to your application's Gemfile:

gem 'email_domain_checker'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install email_domain_checker

Quick Start

require 'email_domain_checker'

# Quick validation
EmailDomainChecker.valid?("user@example.com", validate_domain: false) # => true

# Domain validation with MX records
EmailDomainChecker.domain_valid?("user@example.com", check_mx: true) # => true/false

# Normalize email
EmailDomainChecker.normalize("User@Example.COM") # => "user@example.com"

Documentation

📖 Full Documentation - Complete usage guide, API reference, and examples

Features

• ✅ Email format validation
• ✅ Domain existence validation
• ✅ MX record checking
• ✅ A record checking
• ✅ Email normalization
• ✅ ActiveModel/ActiveRecord integration
• ✅ DNS result caching (memory and Redis)
• ✅ Test mode for development

Development

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 the created tag, and push the .gem file to rubygems.org.

Building Documentation Locally

To build and preview the documentation locally:

# Install Python dependencies
pip install -r requirements.txt

# Start development server (with live reload)
mkdocs serve

# Build static site
mkdocs build

The documentation will be available at http://127.0.0.1:8000 when using mkdocs serve. The built files will be in the site/ directory when using mkdocs build.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/tatematsu-k/email_domain_checker.

License

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