📧 Go Mail

A cross-platform mail driver for GoLang. Featuring Mailgun, Postal, Postmark, SendGrid, SparkPost & SMTP.

Overview

• ✅ Multiple mail drivers for your needs or even create your own custom Mailer.
• ✅ Direct dependency free, all requests are made with the standard lib http.Client.
• ✅ Send attachments with two struct fields, it's extremely simple.
• ✅ Send CC & BCC messages.
• ✅ Extremely lightweight.

Supported API's

• Mailgun

• Postal

• Postmark

• SendGrid

• SparkPost

• SMTP

Introduction

Go Mail aims to unify multiple popular mail APIs into a singular, easy to use interface. Email sending is seriously simple and great for allowing the developer or end user to choose what platform they use.

cfg := mail.Config{
    URL:         "https://api.eu.sparkpost.com",
    APIKey:      "my-key",
    FromAddress: "[email protected]",
    FromName:    "Gopher",
}

mailer, err := drivers.NewSparkPost(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
    Recipients:  []string{"[email protected]"},
    Subject:     "My email",
    HTML:        "<h1>Hello from Go Mail!</h1>",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

Installation

go get -u github.com/ainsleyclark/go-mail

Docs

Documentation can be found at the Go Docs, but we have included a kick-start guide below to get you started.

Creating a new client:

You can create a new driver by calling the drivers package and passing in a configuration type which is required to create a new mailer. Each platform requires its own data, for example, Mailgun requires a domain, but SparkPost doesn't. This is based of the requirements for the API. For more details see the examples below.

cfg := mail.Config{
	URL:         "https://api.eu.sparkpost.com",
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
	Client:       http.DefaultClient, // Client is optional
}

mailer, err := drivers.NewSparkpost(cfg)
if err != nil {
	log.Fatalln(err)
}

Sending Data:

A transmission is required to transmit to a mailer as shown below. Once send is called, a mail.Response and an error be returned indicating if the transmission was successful.

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
	Headers: map[string]string{
		"X-Go-Mail": "Test",
	},
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

Response:

The mail response is used for debugging and inspecting results of the mailer. Below is the Response type.

// Response represents the data passed back from a successful transmission.
type Response struct {
	StatusCode int         // e.g. 200
	Body       []byte      // e.g. {"result: success"}
	Headers    http.Header // e.g. map[X-Ratelimit-Limit:[600]]
	ID         string      // e.g "100"
	Message    string      // e.g "Email sent successfully"
}

Adding attachments:

Adding attachments to the transmission is as simple as passing a byte slice and filename. Go Mail takes care of the rest for you.

image, err := ioutil.ReadFile("gopher.jpg")
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "plain text",
	Attachments: []mail.Attachment{
		{
			Filename: "gopher.jpg",
			Bytes:    image,
		},
	},
}

Examples

Mailgun

cfg := mail.Config{
URL:         "https://api.eu.mailgun.net", // Or https://api.mailgun.net
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
	Domain:      "my-domain.com",
}

mailer, err := drivers.NewMailgun(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

Postal

cfg := mail.Config{
	URL:         "https://postal.example.com",
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
}

mailer, err := drivers.NewPostal(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

Postmark

cfg := mail.Config{
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
}

mailer, err := drivers.NewPostmark(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

SendGrid

cfg := mail.Config{
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
}

mailer, err := drivers.NewSendGrid(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

SMTP

cfg := mail.Config{
	URL:         "smtp.gmail.com",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
	Password:    "my-password",
	Port:        587,
}

mailer, err := drivers.NewSMTP(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

SparkPost

cfg := mail.Config{
	URL:         "https://api.eu.sparkpost.com", // Or https://api.sparkpost.com/api/v1
	APIKey:      "my-key",
	FromAddress: "[email protected]",
	FromName:    "Gopher",
}

mailer, err := drivers.NewSparkPost(cfg)
if err != nil {
	log.Fatalln(err)
}

tx := &mail.Transmission{
	Recipients: []string{"[email protected]"},
	CC:         []string{"[email protected]"},
	BCC:        []string{"[email protected]"},
	Subject:    "My email",
	HTML:       "<h1>Hello from Go Mail!</h1>",
	PlainText:  "Hello from Go Mail!",
}

result, err := mailer.Send(tx)
if err != nil {
	log.Fatalln(err)
}

fmt.Printf("%+v\n", result)

Writing a Mailable

You have the ability to create your own custom Mailer by implementing the singular method interface shown below.

type Mailer interface {
	// Send accepts a mail.Transmission to send an email through a particular
	// driver/provider. Transmissions will be validated before sending.
	//
	// A mail.Response or an error will be returned. In some circumstances
	// the body and status code will be attached to the response for debugging.
	Send(t *mail.Transmission) (mail.Response, error)
}

Debugging

To debug any errors or issues you are facing with Go Mail, you are able to change the Debug variable in the mail package. This will write the HTTP requests in curl to stdout. Additional information will also be displayed in the errors such as method operations.

mail.Debug = true

Development

Setup

To get set up with Go Mail simply clone the repo and run the following:

go get github.com/vektra/mockery/v2/.../
make setup
make mocks

Env

All secrets are contained within the .env file for testing drivers. To begin with, make a copy of the .env.example file and name it .env. You can the set the environment variables to match your credentials for the mail drivers.

You can set the recipients of emails by modifying the EMAIL variables as show below.

• EMAIL_TO: Recipients of test emails in a comma delimited list.
• EMAIL_CC: CC recipients of test emails in a comma delimited list.
• EMAIL_BCC: BCC recipients of test emails in a comma delimited list.

Testing

To run all driver tests, execute the following command:

make test-driver

To run a specific driver test, prepend the driver flag as show below:

make test-driver driver=sparkpost

The driver flag can be one of the following:

• mailgun
• postal
• postmark
• sendgrid
• smtp
• sparkpost

Contributing

We welcome contributors, but please read the contributing document before making a pull request.

Credits

Shout out to the incredible Maria Letta for her excellent Gopher illustrations.

Licence

Code Copyright 2022 Go Mail. Code released under the MIT Licence.