realmail - Only valid real emails

Realmail is a configurable 📨 email validator written in Golang. You can verify email via Regex, DNS, SMTP and even more, hopefully :-) Spend less on marketing, filter fake users by making sure emails are not only valid but real as well.

Please Note: Work is still in progress, not taking pull requests for now. Please add any suggestions to "issues" section. Thanks.

Synopsis
Features
Requirements
Installation
Usage
- Configuration features
  - Creating configuration
  - Using configuration
- Validation features
  - Regex validation
    - With default regex pattern
    - With custom regex pattern
Contributing
License

Synopsis

Email validation is a hard enough. As a developer, I have encountered the problem of validating real emails in several business use cases and requirements. There are a number of different ways to validate an email address and they must conform with the best practices and provide proper validation. realmail package helps you validate emails via:

Regex pattern
Presence of DNS records
Real existence of email account on a current email server.

Syntax Checking: Checks the email addresses via regex pattern.

Mail Server Existence Check: Checks the availability of the email address domain using DNS records.

Mail Existence Check: Checks if the email address really exists and can receive email via SMTP connections and email-sending emulation techniques.

Features

Configurable validator, validate only what you need
Supporting of internationalized emails (EAI)

Requirements

Golang 1.19+

Installation

Install realmail:

go get github.com/Double-DOS/realmail
go install -i github.com/Double-DOS/realmail

Import realmail dependency into your code:

package main

import "github.com/Double-DOS/realmail"

Usage

Configuration features

You can use global package configuration or custom independent configuration. Available configuration options (growing list):

verifier email
verifier domain
email pattern

Creating configuration

TO access all the library features, you must first create configuration struct first. Please use realmail.NewConfiguration() built-in constructor to create a valid configuration as in the example below:

import "github.com/Double-DOS/realmail"

configuration := realmail.NewConfiguration(
  ConfigurationSetting{
    // Required parameter. Must be an existing email on behalf of which verification will be
    // performed
    VerifierEmail: "verifier@example.com",

    // Optional parameter. Must be an existing domain on behalf of which verification will be
    // performed. By default verifier domain based on verifier email
    VerifierDomain: "somedomain.com",

    // Optional parameter. You can override default regex pattern
    EmailPattern: `\A.+@(.+)\z`,


    // Optional parameter. You can predefine default validation type for
    // realmail.StartValidation("email@email.com", configuration) call without type-parameter
    // Available validation types: "regex", "mx", "mx_blacklist", "smtp"
    // note: only regex validation is currently supported as other validation destinations
    // are still in progress.
    ValidationDestination: "mx",
  },
)

Using configuration

import "github.com/Double-DOS/realmail"

configuration := realmail.NewConfiguration(realmail.ConfigurationSetting{VerifierEmail: "verifier@example.com"})


// Returns a pointer to a validation bus that holds information about
// the status of the validation, its success or failure
// and validation errors where they occur.
realmail.StartValidation("some@email.com", configuration)

// Returns boolean status of the validation
realmail.IsReal("email@example.com", configuration, "regex")

Regex validation

By default this validation not performs strictly following RFC 5322 standard, so you can override realmail default regex pattern if you want.

Example of usage:

With default regex pattern

import "github.com/Double-DOS/realmail"

configuration := realmail.NewConfiguration(
  realmail.ConfigurationSetting{
    VerifierEmail: "verifier@example.com",
  },
)

realmail.StartValidation("email@example.com", configuration, "regex") // returns pointer to ValidatorResult with validation details and error

With custom regex pattern

You should define your custom regex pattern in the configuration setting before calling the StartValidation() method

import "github.com/Double-DOS/realmail"

configuration := realmail.NewConfiguration(
  realmail.ConfigurationSetting{
    VerifierEmail: "verifier@example.com",
    EmailPattern: `\A(.+)@(.+)\z`,
  },
)

realmail.StartValidation("email@example.com", configuration, "regex") // returns pointer to ValidatorResult with validation details and error
realmail.IsReal("email@example.com", configuration, "regex") // returns true
realmail.IsReal("not_email", configuration, "regex") // returns false

Contributing

Although the first version of the project is still in progress, this project is intended to be a safe, welcoming space for collaboration and contribution.

midedickson/realmail