emailverifier

README

email-verifier

✉️ A Go library for email verification without sending any emails.

Features

• Email Address Validation: validates if a string contains a valid email.
• Email Verification Lookup via SMTP: performs an email verification on the passed email
• MX Validation: checks the DNS MX records for the given domain name
• Misc Validation: including Free email provider check, Role account validation, Disposable emails address (DEA) validation
• Email Reachability: checks how confident in sending an email to the address

Install

Use go get to install this package.

go get -u github.com/AfterShip/email-verifier

Usage

Basic usage

Use Verify method to verify an email address with different dimensions

package main

import (
    "fmt"

    "github.com/AfterShip/email-verifier"
)

var (
    verifier = emailverifier.NewVerifier()
)

func main() {

    email := "example@exampledomain.org"
    ret, err := verifier.Verify(email)
    if err != nil {
        fmt.Println("check email failed: ", err)
        return
    }

    fmt.Println("email validation result", ret)
}

Email verification Lookup

Use CheckSMTP to performs an email verification lookup via SMTP.

var (
    verifier = emailverifier.
        NewVerifier().
        EnableSMTPCheck()
)

func main() {

    domain := "domain.org"
    ret, err := verifier.CheckSMTP(domain)
    if err != nil {
        fmt.Println("check smtp failed: ", err)
        return
    }

    fmt.Println("smtp validation result: ", ret)

}

Note: because most of the ISPs block outgoing SMTP requests through port 25 to prevent email spamming, the module will not perform SMTP checking by default. You can initialize the verifier with EnableSMTPCheck() to enable such capability if port 25 is usable.

Misc Validation

To check if an email domain is disposable via IsDisposable

var (
    verifier = emailverifier.
        NewVerifier().
        EnableAutoUpdateDisposable()
)

func main() {
    domain := "domain.org"
    ret := verifier.IsDisposable(domain)
    fmt.Println("misc validation result: ", ret)
}

Note: It is possible to automatically update the disposable domains daily by initializing verifier with EnableAutoUpdateDisposable()

For more detailed documentation, please check on godoc.org 👉 email-verifier

Similar Libraries Comparison

	email-verifier	trumail	check-if-email-exists	freemail
Features	〰️	〰️	〰️	〰️
Disposable email address validation	✅	✅, but not available in free lib	✅	✅
Disposable address autoupdate	✅	🤔	❌	❌
Free email provider check	✅	✅, but not available in free lib	❌	✅
Role account validation	✅	❌	✅	❌
Syntax validation	✅	✅	✅	❌
Email reachability	✅	✅	✅	❌
DNS records validation	✅	✅	✅	❌
Email deliverability	✅	✅	✅	❌
Mailbox disabled	✅	✅	✅	❌
Full inbox	✅	✅	✅	❌
Host exists	✅	✅	✅	❌
Catch-all	✅	✅	✅	❌
Gravatar	✅	✅, but not available in free lib	❌	❌
Typo check	🔜	✅, but not available in free lib	❌	❌
Honeyport dection	🔜	❌	❌	❌
Bounce email check	🔜	❌	❌	❌
Tech	〰️	〰️	〰️	〰️
Provide API	🔜	✅	✅	❌
Free API	🔜	❌	❌	❌
Language	Go	Go	Rust	JavaScript
Active maintain	✅	❌	✅	✅
High Performance	✅	❌	✅	✅

FAQ

The library hangs/takes a long time after 30 seconds when performing email verification lookup via SMTP

Most ISPs block outgoing SMTP requests through port 25 to prevent email spamming. email-verifier needs to have this port open to make a connection to the email's SMTP server. With the port being blocked, it is not possible to perform such checking, and it will instead hang until timeout error. Unfortunately, there is no easy workaround for this issue.

For more information, you may also visit this StackOverflow thread.

The output shows "connection refused" in the smtp.error field.

This error can also be due to SMTP ports being blocked by the ISP, see the above answer.

What does reachable: "unknown" means

This means that the server does not allow real-time verification of an email right now, or the email provider is a catch-all email server.

Credits

• trumail
• check-if-email-exists
• disposable domains from disposable/disposable
• free provider data from willwhite/freemail

Contributing

For details on contributing to this repository, see the contributing guide.

License

This package is licensed under MIT license. See LICENSE for details.

Documentation

Index

• Constants
• func GenerateRandomEmail(domain string) string
• func IsAddressValid(email string) bool
• type Gravatar
• type LookupError
  • func ParseSMTPError(err error) *LookupError
  • func (e *LookupError) Error() string
• type Mx
• type Result
• type SMTP
• type Syntax
• type Verifier
  • func NewVerifier() *Verifier
  • func (v *Verifier) CheckGravatar(email string) (*Gravatar, error)
  • func (v *Verifier) CheckMX(domain string) (*Mx, error)
  • func (v *Verifier) CheckSMTP(domain, username string) (*SMTP, error)
  • func (v *Verifier) DisableAutoUpdateDisposable() *Verifier
  • func (v *Verifier) DisableGravatarCheck() *Verifier
  • func (v *Verifier) DisableSMTPCheck() *Verifier
  • func (v *Verifier) EnableAutoUpdateDisposable() *Verifier
  • func (v *Verifier) EnableGravatarCheck() *Verifier
  • func (v *Verifier) EnableSMTPCheck() *Verifier
  • func (v *Verifier) FromEmail(email string) *Verifier
  • func (v *Verifier) HelloName(domain string) *Verifier
  • func (v *Verifier) IsDisposable(domain string) bool
  • func (v *Verifier) IsFreeDomain(domain string) bool
  • func (v *Verifier) IsRoleAccount(username string) bool
  • func (v *Verifier) ParseAddress(email string) *Syntax
  • func (v *Verifier) Verify(email string) (*Result, error)

Constants

const (
	// Standard Errors
	ErrTimeout           = "The connection to the mail server has timed out"
	ErrNoSuchHost        = "Mail server does not exist"
	ErrServerUnavailable = "Mail server is unavailable"
	ErrBlocked           = "Blocked by mail server"

	// RCPT Errors
	ErrTryAgainLater           = "Try again later"
	ErrFullInbox               = "Recipient out of disk space"
	ErrTooManyRCPT             = "Too many recipients"
	ErrNoRelay                 = "Not an open relay"
	ErrMailboxBusy             = "Mailbox busy"
	ErrExceededMessagingLimits = "Messaging limits have been exceeded"
	ErrNotAllowed              = "Not Allowed"
	ErrNeedMAILBeforeRCPT      = "Need MAIL before RCPT"
	ErrRCPTHasMoved            = "Recipient has moved"
)

Functions

func GenerateRandomEmail

func GenerateRandomEmail(domain string) string

GenerateRandomEmail generates a random email address using the domain passed. Used primarily for checking the existence of a catch-all address

func IsAddressValid

func IsAddressValid(email string) bool

IsAddressValid checks if email address is formatted correctly by using regex

Types

type Gravatar

type Gravatar struct {
	HasGravatar bool   // whether has gravatar
	GravatarUrl string // gravatar url
}

Gravatar is detail about the Gravatar

type LookupError

type LookupError struct {
	Message string `json:"message" xml:"message"`
	Details string `json:"details" xml:"details"`
}

LookupError is an MX dns records lookup error

func ParseSMTPError

func ParseSMTPError(err error) *LookupError

ParseSMTPError receives an MX Servers response message and generates the corresponding MX error

func (*LookupError) Error

func (e *LookupError) Error() string

type Mx

type Mx struct {
	HasMXRecord bool      // whether has 1 or more MX record
	Records     []*net.MX // represent DNS MX records
}

Mx is detail about the Mx host

type Result

type Result struct {
	Email        string    `json:"email"`          // passed email address
	Disposable   bool      `json:"disposable"`     // is this a DEA (disposable email address)
	Reachable    string    `json:"reachable"`      // an enumeration to describe whether the recipient address is real
	RoleAccount  bool      `json:"role_account"`   // is account a role-based account
	Free         bool      `json:"free"`           // is domain a free email domain
	Syntax       *Syntax   `json:"syntax"`         // details about the email address syntax
	HasMxRecords bool      `json:"has_mx_records"` // whether or not MX-Records for the domain
	SMTP         *SMTP     `json:"smtp"`           // details about the SMTP response of the email
	Gravatar     *Gravatar `json:"gravatar"`       // whether or not have gravatar for the email
}

Result is the result of Email Verification

type SMTP

type SMTP struct {
	HostExists  bool `json:"host_exists"` // is the host exists?
	FullInbox   bool `json:"full_inbox"`  // is the email account's inbox full?
	CatchAll    bool `json:"catch_all"`   // does the domain have a catch-all email address?
	Deliverable bool `json:"deliverable"` // can send an email to the email server?
	Disabled    bool `json:"disabled"`    // is the email blocked or disabled by the provider?
}

SMTP stores all information for SMTP verification lookup

type Syntax

type Syntax struct {
	Username string `json:"username"`
	Domain   string `json:"domain"`
	Valid    bool   `json:"valid"`
}

Syntax stores all information about an email Syntax

type Verifier

type Verifier struct {
	// contains filtered or unexported fields
}

Verifier is an email verifier. Create one by calling NewVerifier

func NewVerifier

func NewVerifier() *Verifier

NewVerifier creates a new email verifier

func (*Verifier) CheckGravatar

func (v *Verifier) CheckGravatar(email string) (*Gravatar, error)

CheckGravatar will return the Gravatar records for the given email.

func (*Verifier) CheckMX

func (v *Verifier) CheckMX(domain string) (*Mx, error)

CheckMX will return the DNS MX records for the given domain name sorted by preference.

func (*Verifier) CheckSMTP

func (v *Verifier) CheckSMTP(domain, username string) (*SMTP, error)

CheckSMTP performs an email verification on the passed domain via SMTP

func (*Verifier) DisableAutoUpdateDisposable

func (v *Verifier) DisableAutoUpdateDisposable() *Verifier

DisableAutoUpdateDisposable stops previously started schedule job

func (*Verifier) DisableGravatarCheck

func (v *Verifier) DisableGravatarCheck() *Verifier

DisableGravatarCheck disables check gravatar,

func (*Verifier) DisableSMTPCheck

func (v *Verifier) DisableSMTPCheck() *Verifier

DisableSMTPCheck disables check email by smtp

func (*Verifier) EnableAutoUpdateDisposable

func (v *Verifier) EnableAutoUpdateDisposable() *Verifier

EnableAutoUpdateDisposable enables update disposable domains automatically

func (*Verifier) EnableGravatarCheck

func (v *Verifier) EnableGravatarCheck() *Verifier

EnableGravatarCheck enables check gravatar, we don't check gravatar by default

func (*Verifier) EnableSMTPCheck

func (v *Verifier) EnableSMTPCheck() *Verifier

EnableSMTPCheck enables check email by smtp, for most ISPs block outgoing SMTP requests through port 25, to prevent spam, we don't check smtp by default

func (*Verifier) FromEmail

func (v *Verifier) FromEmail(email string) *Verifier

FromEmail sets the emails to use in the `MAIL FROM:` smtp command

func (*Verifier) HelloName

func (v *Verifier) HelloName(domain string) *Verifier

HelloName sets the name to use in the `EHLO:` SMTP command

func (*Verifier) IsDisposable

func (v *Verifier) IsDisposable(domain string) bool

IsDisposable checks if domain is a disposable domain

func (*Verifier) IsFreeDomain

func (v *Verifier) IsFreeDomain(domain string) bool

IsFreeDomain checks if domain is a free domain

func (*Verifier) IsRoleAccount

func (v *Verifier) IsRoleAccount(username string) bool

IsRoleAccount checks if username is a role-based account

func (*Verifier) ParseAddress

func (v *Verifier) ParseAddress(email string) *Syntax

ParseAddress attempts to parse an email address and return it in the form of an Syntax

func (*Verifier) Verify

func (v *Verifier) Verify(email string) (*Result, error)

Verify performs address, misc, mx and smtp checks