Golang send email: Send transactional email with Go in minutes

                            

                                go get github.com/mailjet/mailjet-apiv3-go/v4
                            
                        

                            

                                export MJ_APIKEY_PUBLIC=your_api_key
export MJ_APIKEY_PRIVATE=your_secret_key
export SENDER_EMAIL=your_verified_sender@yourdomain.com
                            
                        

                            

                                package main

import (
    "fmt"
    "log"
    "os"

    "github.com/mailjet/mailjet-apiv3-go/v4"
)

func main() {
    mj := mailjet.NewMailjetClient(os.Getenv("MJ_APIKEY_PUBLIC"), os.Getenv("MJ_APIKEY_PRIVATE"))

    msgs := []mailjet.InfoMessagesV31{
        {
            From: &mailjet.RecipientV31{Email: os.Getenv("SENDER_EMAIL"), Name: "Go App"},
            To: &mailjet.RecipientsV31{
                {Email: "recipient@example.com", Name: "Recipient"},
            },
            Subject:  "Hello from Go + Mailjet",
            TextPart: "This is a plain-text fallback.",
            HTMLPart: "<h3>Hello from Go + Mailjet</h3><p>It works.</p>",
        },
    }

    messages := mailjet.MessagesV31{Info: msgs}
    res, err := mj.SendMailV31(&messages)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Status: %+v\n", res)
}

                            
                        

                            

                                package main

import (
    "net/smtp"
    "os"
)

func main() {
    host := "in-v3.mailjet.com"
    auth := smtp.PlainAuth("", os.Getenv("MJ_APIKEY_PUBLIC"), os.Getenv("MJ_APIKEY_PRIVATE"), host)

    to := []string{"recipient@example.com"}
    from := "sender@yourdomain.com"
    msg := []byte(
        "To: recipient@example.com\r\n" +
            "From: Go App <sender@yourdomain.com>\r\n" +
            "Subject: SMTP from Go via Mailjet\r\n" +
            "MIME-Version: 1.0\r\n" +
            "Content-Type: text/html; charset=UTF-8\r\n\r\n" +
            "<p>Hello via SMTP</p>",
    )

    // Port 587 (TLS) or 465 (SSL) are common choices
    err := smtp.SendMail(host+":587", auth, from, to, msg)
    if err != nil {
        log.Fatal(err)
    }
}

                            
                        

                            

                                msgs := []mailjet.InfoMessagesV31{
    {
        From:              &mailjet.RecipientV31{Email: os.Getenv("SENDER_EMAIL"), Name: "Go App"},
        To:                &mailjet.RecipientsV31{{Email: "recipient@example.com", Name: "Terry"}},
        TemplateID:        123456,    // replace with your template ID
        TemplateLanguage:  true,      // enable Mailjet templating language
        Variables:         map[string]any{"first_name": "Terry", "plan": "Pro"},
        Subject:           "Welcome, {{var:first_name:\"there\"}}",
    },
}

                            
                        

                            

                                // Read and base64-encode your files first, then:
msgs := []mailjet.InfoMessagesV31{
    {
        From: &mailjet.RecipientV31{Email: os.Getenv("SENDER_EMAIL")},
        To:   &mailjet.RecipientsV31{{Email: "recipient@example.com"}},
        Subject:  "Invoice attached + inline logo",
        HTMLPart: `<p>Thanks for your purchase!</p><img src="cid:logo1" alt="Company Logo">`,
        Attachments: &[]mailjet.AttachmentV31{
            {
                ContentType:   "application/pdf",
                Filename:      "invoice.pdf",
                Base64Content: "<BASE64_STRING>", // your base64-encoded PDF
            },
        },
        InlinedAttachments: &[]mailjet.InlinedAttachmentV31{
            {
                AttachmentV31: mailjet.AttachmentV31{
                    ContentType:   "image/png",
                    Filename:      "logo.png",
                    Base64Content: "<BASE64_PNG>", // your base64-encoded image
                },
                ContentID: "logo1", // referenced in HTML as cid:logo1
            },
        },
    },
}
                            
                        

                            

                                msgs := []mailjet.InfoMessagesV31{
    {
        From: &mailjet.RecipientV31{Email: os.Getenv("SENDER_EMAIL")},
        To:   &mailjet.RecipientsV31{{Email: "user1@example.com"}},
        Subject: "Welcome, User 1!",
        HTMLPart: "<p>Hello User 1</p>",
    },
    {
        From: &mailjet.RecipientV31{Email: os.Getenv("SENDER_EMAIL")},
        To:   &mailjet.RecipientsV31{{Email: "user2@example.com"}},
        Subject: "Welcome, User 2!",
        HTMLPart: "<p>Hello User 2</p>",
    },
}

res, err := mj.SendMailV31(&mailjet.MessagesV31{Info: msgs})
if err != nil {
    log.Fatal(err)
}

// Process results - each message gets its own status and ID
for i, result := range res.ResultsV31 {
    fmt.Printf("Message %d: Status=%s, MessageID=%d\n", i, result.Status, result.To[0].MessageID)
}

                            
                        

                            

                                package main

import (
    "encoding/json"
    "net/http"
    "log"
)

type MailjetEvent struct {
    Event     string `json:"event"`
    Time      int64  `json:"time"`
    MessageID int64  `json:"MessageID"`
    Email     string `json:"email"`
    URL       string `json:"url,omitempty"`    // for click events
    Error     string `json:"error,omitempty"`  // for bounce/error events
}

func webhookHandler(w http.ResponseWriter, r *http.Request) {
    defer r.Body.Close()

    var events []MailjetEvent
    if err := json.NewDecoder(r.Body).Decode(&events); err != nil {
        http.Error(w, "bad request", http.StatusBadRequest)
        return
    }

    // Process events (consider using a queue for production)
    for _, event := range events {
        switch event.Event {
        case "sent":
            log.Printf("Message %d sent to %s", event.MessageID, event.Email)
        case "open":
            log.Printf("Message %d opened by %s", event.MessageID, event.Email)
        case "click":
            log.Printf("Message %d clicked by %s (URL: %s)", event.MessageID, event.Email, event.URL)
        case "bounce":
            log.Printf("Message %d bounced for %s: %s", event.MessageID, event.Email, event.Error)
        }
    }

    // Always return 200 to acknowledge receipt
    w.WriteHeader(http.StatusOK)
}

func main() {
    http.HandleFunc("/mj/events", webhookHandler)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

                            
                        

                            

                                // For US region accounts
mj := mailjet.NewMailjetClient(apiKey, secretKey)
mj.SetAPIBase("https://api.us.mailjet.com/v3.1/")